• Title/Summary/Keyword: Cube

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Diameter, Fault Diameter and Average Distance between Two Nodes in Z-cube Network (Z-cube 네트워크의 직경, 고장직경과 정점간 평균거리)

  • Gwon, Gyeong-Hui;Lee, Gye-Seong
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.1
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    • pp.75-83
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    • 1999
  • recently, a new hypercube-like interconnection network, the Z-cube, was proposed. The Z-cube retains most good topological properties, however, its node degree is 3/4 of hypercube's one. Considering hardware implementations, the Z-cube is a good alternative to the hypercube. In this paper, we obtained the diameter, fault diameter and the average distance between two nodes to evaluate the communication performance of the Z-cube. The recursive structure, the shortest path between two nodes I Z-cube and recurrence relation on the average distance were deduced, and node disjoint path was introduced. Although it is generally expected that the communication performance in an interconnection network with reduced node degree falls as much as that, this paper shows that the Z-cube's diameter is the same as the hypercube's one and the average distance between two nodes in Z-cube is about 1.125 times the average distance between two nodes in the hypercube and the fault diameter of Z-cube ranges approximately from 1.4times to 1.7times the fault diameter of the hypercube.

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Design of Ground Station System for CubeSat STEP Cube Lab. (큐브위성 STEP Cube Lab.의 지상국 시스템 설계)

  • Jeon, Younghyeon;Chae, Bonggeon;Jeong, Hyeonmo;Jeon, Seongyong;Oh, Hyunung
    • Journal of Aerospace System Engineering
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    • v.6 no.4
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    • pp.34-39
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    • 2012
  • CubeSats classified as pico-class satellite require a ground station to track the satellite, transmit a command, and receive an on-orbit data such as SOH (State-of-Health) and mission data according to the operation plan. For this, ground station system has to be properly designed to perform a communication to with the satellite with enough up- and down-link budgets. In this study, a conceptual design of the ground station has been performed for the CubeSat named as STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project). The paper includes a ground station hardware interface design, link budget analysis and a ground station software realization. In addition, the operation plan of the ground station has been established considering the STEP Cube Lab. mission requirements.

Hilbert Cube for Spatio-Temporal Data Warehouses (시공간 데이타웨어하우스를 위한 힐버트큐브)

  • 최원익;이석호
    • Journal of KIISE:Databases
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    • v.30 no.5
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    • pp.451-463
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    • 2003
  • Recently, there have been various research efforts to develop strategies for accelerating OLAP operations on huge amounts of spatio-temporal data. Most of the work is based on multi-tree structures which consist of a single R-tree variant for spatial dimension and numerous B-trees for temporal dimension. The multi~tree based frameworks, however, are hardly applicable to spatio-temporal OLAP in practice, due mainly to high management cost and low query efficiency. To overcome the limitations of such multi-tree based frameworks, we propose a new approach called Hilbert Cube(H-Cube), which employs fractals in order to impose a total-order on cells. In addition, the H-Cube takes advantage of the traditional Prefix-sum approach to improve Query efficiency significantly. The H-Cube partitions an embedding space into a set of cells which are clustered on disk by Hilbert ordering, and then composes a cube by arranging the grid cells in a chronological order. The H-Cube refines cells adaptively to handle regional data skew, which may change its locations over time. The H-Cube is an adaptive, total-ordered and prefix-summed cube for spatio-temporal data warehouses. Our approach focuses on indexing dynamic point objects in static spatial dimensions. Through the extensive performance studies, we observed that The H-Cube consumed at most 20% of the space required by multi-tree based frameworks, and achieved higher query performance compared with multi-tree structures.

A Study on The Application of Inclusion-Exclusion Method in Soma Cube Activity (소마큐브(Soma Cube) 활동에서 포함-배제 방법의 활용에 대한 연구)

  • Shim, Sang-Kil;Hwang, Sun-Wook
    • The Mathematical Education
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    • v.48 no.1
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    • pp.33-45
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    • 2009
  • The purpose of this article is to study characteristics of Soma Cube in combinatorial-geometric point of view, and to present basic substances and direction for efficient Soma cube activities in school mathematics upon systematical analysis of methods of finding solutions using Inclusion-Exclusion Method. We can apply Inclusion-Exclusion Method to find all possible solutions in Soma Cube activities not as trial-and-error method but as analytical method. Because Inclusion-Exclusion Method can reduce the number of problem-solving variables by making high conjunction in the choice of pieces. Soma cube pieces can be sorted as 'flat' ones and 'non-flat' ones, which would be another effective method in the manipulation of Soma Cube pieces.

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Hamiltonian Paths in Restricted Hypercube-Like Graphs with Edge Faults (에지 고장이 있는 Restricted Hypercube-Like 그래프의 해밀톤 경로)

  • Kim, Sook-Yeon;Chun, Byung-Tae
    • The KIPS Transactions:PartA
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    • v.18A no.6
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    • pp.225-232
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    • 2011
  • Restricted Hypercube-Like (RHL) graphs are a graph class that widely includes useful interconnection networks such as crossed cube, Mobius cube, Mcube, twisted cube, locally twisted cube, multiply twisted cube, and generalized twisted cube. In this paper, we show that for an m-dimensional RHL graph G, $m{\geq}4$, with an arbitrary faulty edge set $F{\subset}E(G)$, ${\mid}F{\mid}{\leq}m-2$, graph $G{\setminus}F$ has a hamiltonian path between any distinct two nodes s and t if dist(s, V(F))${\neq}1$ or dist(t, V(F))${\neq}1$. Graph $G{\setminus}F$ is the graph G whose faulty edges are removed. Set V(F) is the end vertex set of the edges in F and dist(v, V(F)) is the minimum distance between vertex v and the vertices in V(F).

On-orbit Thermal Environment Characteristic according to Launch Time of CubeSat STEP Cube Lab-II (초소형위성 STEP Cube Lab-II의 발사시간 변화에 따른 궤도 열환경 특성 분석)

  • Son, Min-Young;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.15 no.5
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    • pp.89-97
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    • 2021
  • STEP Cube Lab-II (Cube Laboratory for Space Technology Experimental Project-II) is a 6U Cube satellite equipped with optical and infrared cameras for monitoring Mt. Paektu volcanic eruption signs and earth observation in the Korean peninsula. To guarantee successful mission operation of the cube satellite in orbit, thermal design is essential for the electronic equipment, and must be kept within the allowable temperature range during the mission period. Thus, it is necessary to analyze the predictable orbital thermal environment. The STEP Cube Lab-II is launched through the KSLV-II, however, the operation orbit has not been determined due to the unknown launch time. In this study, we performed a thermal analysis of the satellite and investigated the heat flux according to launch time to analyze the worst orbital conditions that could occur.

WALL EFFECTS ON LAMINAR FLOW OVER A CUBE (정육면체 주위 층류 유동에 근처 벽면이 미치는 영향)

  • Kim, Dong-Joo
    • Journal of computational fluids engineering
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    • v.16 no.1
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    • pp.83-89
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    • 2011
  • Laminar flow over a cube near a plane wall is numerically investigated in order to understand the effects of the cube-wall gap on the flow characteristics as well as the drag and lift coefficients. The main focus is placed on the three-dimensional vortical structures and its relation to the lift force applied on the cube. Numerical simulations are performed for the Reynolds numbers between 100 and 300, covering several different flow regimes. Without a wall nearby, the flow at Re=100 is planar symmetric with no vortical structure in the wake. However, when the wall is located close to the cube, a pair of streamwise vortices is induced behind the cube. At Re=250, the wall strengthens the existing streamwise vortices and elongates them in the streamwise direction. As a result, the lift coefficients at Re=100 and 250 increase as the cube-wall gap decreases. On the other hand, without a wall, vortex shedding takes place at Re=300 in the form of a hairpin vortex whose strength changes in time. The head of hairpin vortex or loop vortex, which is closely related to the lift force, seems to disappear due to the nearby wall. Therefore, unlike at Re=100 and 250, the lift coefficient tends to decrease more or less as the cube approaches the wall.

Design of Ground Station System for CubeSat STEP Cube Lab. (큐브위성 STEP Cube Lab.의 지상국 시스템 개발)

  • Jeon, Younghyeon;Chae, Bonggeon;Jeong, Hyeonmo;Jeon, Seongyong;Oh, Hyunung
    • Journal of Aerospace System Engineering
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    • v.9 no.4
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    • pp.37-42
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    • 2015
  • The CubeSats is classified as a pico-class satellite which requires a ground station to track the satellite, transmit commands, and receive an on-orbit data such as SOH (State-of-Health) and mission data according to the operation plan. In order to this, the ground station system has to be properly designed to perform a communication to with the satellite with enough up- and down-link budgets. In this study, a conceptual design of the ground station has been performed for the CubeSat named as STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project). The paper includes a ground station hardware interface design, a link budget analysis and a ground station software realization. In addition, the operation plan of the ground station has been established considering the STEP Cube Lab. mission requirements.