• Title/Summary/Keyword: initial trace

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Mass inflow history of satellite systems around a dwarf galaxy

  • Chun, Kyungwon;Shin, Jihye;Kim, Sungsoo S.
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.63.4-64
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    • 2016
  • We aim to investigate inflow history of matters that fall into the satellite systems around a dwarf galaxy in Lambda-Cold Dark Matter model. Each satellite system has unique properties because all satellite systems have different mass inflow history by environments and/or the events such as cosmic reionization and merging with other halos. To trace mass inflow history of the satellite systems, we perform three different cosmological zoom simulations whose galaxy mass is ${\sim}10^{10}M_{sun}$. Each initial zoom simulation covers a cubic box of $1Mpc/h^3$ with 17 million particles. Particle mass for dark matter (DM) and gas components is $M_{DM}=4.1{\times}10^3M_{sun}$ and $M_{gas}=7.9{\times}10^2M_{sun}$, respectively. Thus, each satellite system is resolved with more than hundreds - thousands of particles. We analyze the influence of the gravitational interaction with host galaxy, baryonic matter inflow by various cooling mechanisms, and merging events with other halos on the mass inflow history of satellite systems.

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Internal flow visualization of an evaporating droplet placed on heated metal plate (가열된 금속표면에 놓인 증발하는 액적의 내부유동 가시화)

  • Park, Chang-Seok;Lim, Hee-Chang
    • Journal of the Korean Society of Visualization
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    • v.15 no.1
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    • pp.25-31
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    • 2017
  • This study aims to visualize the Marangoni flow inside a droplet placed on heated hydrophobic surface and to measure its internal velocity field. The experimental result shows that the internal velocity increases with the increase of the plate temperature. In addition, the temperature difference induces the initial flow and drives the Marangoni circulation inside the droplet as soon as the evaporation starts (i.e. the thermal Marangoni flow). The fluorescence particles in the droplet trace two large-scale counter-rotating vortex pairs yielding the downwards flow along the vertical central axis. These vortex pairs gradually become small and move towards the contact line as time goes by, and this Marangoni flow sustains only for a half of the total evaporation time.

FCST, Its Foundation and Early History (FCST의 초기 역사)

  • Yin, Chang Shik;Lee, Young-Jun
    • Journal of TMJ Balancing Medicine
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    • v.1 no.1
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    • pp.9-12
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    • 2011
  • Objectives: Functional Cerebrospinal Therapy (FCST) is a rather new physiologic therapeutics. It has passed about two decades since its basic idea was founded. This study briefly reviewed its early history. Methods: The first FCST patient was a stroke patient in the year 1992. Basic ideas of FCST was devised one by one and later developed into a systematic clinical application. The first official lecture was held in the year 2004. Yinyang balance in the meridian-system-based network over the whole body was a mainstay idea. Results: As other stories on newly-developed therapeutics, there was an effort to make a breakthrough for difficult clinical problems, and followed by a creative initial idea along with incessant refinement in the early history of FCST. Conclusions: Patient-centered approaches was a mainspring in the development and refinement of FCST. History of FCST hereafter may well follow the trace.

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Geochemical and Sm-Nd Isotopic Study of Amphibolite from the Muju Area, Korea (무주 지역 각섬암의 지구화학 및 Sm-Nd 동위원소 연구)

  • Lee, Kwang-Sik;Cheong, Chang-Sik;Park, Kye-Hun;Chang, Ho-Wan
    • Economic and Environmental Geology
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    • v.30 no.4
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    • pp.313-320
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    • 1997
  • Geochemical and Sm-Nd isotopic results are reported for amphibolite of the Muju area, Ryeongnam massif. Major and trace element data analyzed indicate that the parental rock of the Muju amphibolite is tholeiitic basalt. The Sm-Nd amphibole-WR-plagioclase data define an isochron corresponding to $1766{\pm}121Ma$ ($1{\sigma}$) (MSWD=1.10) with an initial ratio of $0.51032{\pm}15$. We interpret this age as a metamorphic age of the Muju amphibolite. Tectonic discrimination diagrams clearly fail when they are applied to the Muju amphibolite probably due to compositional variations resulting from crustal contamination and/or degrees of partial melting.

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Supersonic Axisymmetric Minimum Length Nozzle Conception at High Temperature with Application for Air

  • Zebbiche, Toufik
    • International Journal of Aeronautical and Space Sciences
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    • v.9 no.1
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    • pp.1-30
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    • 2008
  • When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect; its state equation remains always valid, except, it is named in more by calorically imperfect gas. The aim of this work is to trace the profiles of the supersonic axisymmetric Minimum Length Nozzle to have a uniform and parallel flow at the exit section, when the stagnation temperature is taken into account, lower than the dissociation threshold of the molecules, and to have for each exit Mach number and stagnation temperature shape of nozzle. The method of characteristics is used with the algorithm of the second order finite differences method. The form of the nozzle has a point of deflection and an initial angle of expansion. The comparison is made with the calorically perfect gas. The application is for air.

A Theoretical Superscalar Microprocessor Performance Model with Limited Functional Units Using Instruction Dependencies (한정된 연산유닛에서 명령어 종속성을 이용하는 수퍼스칼라 프로세서의 이론적 성능 모델)

  • Lee, Jong-Bok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.2
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    • pp.423-428
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    • 2010
  • In the initial design phase of superscalar microprocessors, a performance model is necessary. A theoretic performance model is very useful since performance for various architecture parameters can be obtained by simply computing equations, without repeating simulations, Previous studies established theoretic performance models using the relation between the instruction window size and the issue width, with the penalties due to branch mispredictions and cache misses. However, the study was intended for unlimited number of functional units, which is insufficient for the real case application. This paper proposes a superscalar microprocessor theoretical performance model which also works for the limited functional units. To enhance the accuracy of our limited functional unit model, instruction dependency rates are employed. By using trace-driven data of SPEC 2000 integer programs as input, this paper shows that the theoretically computed performance of superscalar microprocessor with limited number of functional units is quite similar to the measured performance.

Improvement of Continuation Power Flow System Applying the Optimal Load Shedding Algorithm (최적 부하절체 알고리듬을 적용한 연속조류계산의 향상)

  • Song, Hwa-Chang;Lee, Byong-Jun;Kwon, Sae-Hyuk
    • Proceedings of the KIEE Conference
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    • 1998.07c
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    • pp.899-901
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    • 1998
  • Continuation power flow is a tool that can trace the path of the solution from the base stable solution. However, the base stable solution cannot be calculated when the initial system load is too large to operate at a stable operating point. This case is called as unsolvable case. This paper presents implementation of the optimal load shedding algorithm on continuation power flow. It performs steady-state analysis of power systems at unsolvable case that can occur in contingency analysis. Numerical simulation on 20-bus test system demonstrates that the continuation power flow applying the optimal load shedding algorithm is robust at solvable and unsolvable cases.

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Development of a Scheduling System for Mould and Die Manufacturing Factory Using Microsoft Project 98 (Microsoft Project 98을 이용한 금형공장의 일정계획 시스템 개발)

  • Ju, Sang-Yoon;Ok, Kyung-Jin
    • IE interfaces
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    • v.13 no.2
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    • pp.246-252
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    • 2000
  • As moulds and dies are manufactured through complex processes under the make-to-order production environment, it is very difficult that the manufacturing activities as like observance of the due date, trace of the progress, etc are controlled with a real time. In this paper, a schedule-planning system using the commercial software Microsoft Project 98 is developed to control the procedures of mould and die manufacturing with real time. Once an initial schedule is planned from the BOM information in the intranet, it is rescheduled by data collected from machines on the shop floor. The system is suitable to medium- or small-sized manufacturing companies as well as large-sized ones, because it can be installed with a low cost.

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A Comparative Study between LSI and LDA in Constructing Traceability between Functional and Non-Functional Requirements

  • Byun, Sung-Hoon;Lee, Seok-Won
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.7
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    • pp.19-29
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    • 2019
  • Requirements traceability is regarded as one of the important quality attributes in software requirements engineering field. If requirements traceability is guaranteed then we can trace the requirements' life throughout all the phases, from the customers' needs in the early stage of the project to requirements specification, deployment, and maintenance phase. This includes not only tracking the development artifacts that accompany the requirements, but also tracking backwards from the development artifacts to the initial customer requirements associated with them. In this paper, especially, we dealt with the traceability between functional requirements and non-functional requirements. Among many Information Retrieval (IR) techniques, we decided to utilize Latent Semantic Indexing (LSI) and Latent Dirichlet Allocation (LDA) in our research. Ultimately, we conducted an experiment on constructing traceability by using two techniques and analyzed the experiment results. And then we provided a comparative study between two IR techniques in constructing traceability between functional requirements and non-functional requirements.

Playback Quantity-based Proxy Caching Scheme for Continuous Media Data (재생량에 기반한 연속미디어 데이터 프록시 캐슁 기법)

  • Hong, Hyeon-Ok;Im, Eun-Ji;Jeong, Gi-Dong
    • The KIPS Transactions:PartB
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    • v.9B no.3
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    • pp.303-310
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    • 2002
  • In this paper, we propose a proxy caching scheme that stores a portion of a continuous media object or an entire object on the Internet. The proxy stores the initial fraction of a continuous media object and determines the optimal size of the initial fraction of the continuous media object to be cached based on the object popularity. Under the proposed scheme, the initial latency of most clients and the data transferred from a remote server can be reduced and limited cache storage space can be utilized efficiently. Considering the characteristics of continuous media, we also propose the novel popularity for the continuous media objects based on the amount of the data of each object played by the clients. Finally, we have performed trace-driven simulations to evaluate our caching scheme and the popularity for the continuous media objects. Through these simulations, we have verified that our caching scheme, PPC outperforms other well-known caching schemes in terms of BHR, DSR and replacement and that popularity for the continuous media objects based on the amount of the playback data can enhance the performance of caching scheme.