• Title/Summary/Keyword: D/N value

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Magnet applications of HTS wires

  • Oh, Sang-Soo
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.27-34
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    • 2000
  • HTS wires processed by PIT method are now available for magnet applications. But, those wires can not be used over 40 K due to weak link. This leads to necessity of development of coated conductor which can retain high JcJc at high field in liquid nitrogen. In this paper, various technical issues and the R&D status for both PIT wires and coated conductor were discussed. The difference of coated conductor's processes were also investigated and summarized. Various requirements for a design of HTS magnets were discussed. Anisostropic JcJc property with respect to magnetic field was considered to determine the coil's critical current. Low n value is a critical parameter to degrade a field stability with respect to time for a persistent mode HTS magnet. The relation between the margin of operation current and n value was investigated. Prototype HTS magnets with PIT wires are being developed for various applications such as crystal growth, MRI, magnetic separator and etc. HTS magnets will come into wide use in various fields of industries if the HTS wires with a low performance cost is developed.

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Evaluation of Mechanical Properties of AZ31B for Sheet Metal Forming at Warm and High Temperature (온간, 열간 판재 성형을 위한 AZ31B의 기계적 성질 평가)

  • Choo D. K.;Kim W. Y.;Lee J. H.;Kang C. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.256-259
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    • 2004
  • In the present study, AZ31B sheets has a bad formability in room temperature, but the formability is improved significantly as increasing the temperature because of rolled magnesium alloy sheet has a hexagonal closed packed structure (HCP) and a plastic anisotropy. In this paper, after tensile test in various temperatures, strain rate, show the tensile mechanical properties, yield and ultimate strength, K-value, work hardening exponent(n), strain rate sensitivity(m). As temperature increased, yield, ultimate strength and K-value, work hardening exponent(n) are decreased but strain rate sensitivity(m) is increased. As cross-head-speed increased, yield, ultimate strength and K-value, work hardening exponent(n) are increased. And according to the temperature, how change the plastic anisotropy factor R. In addition, we observed how temperatures and cross-head-speed effect on microstructure.

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On the Counter Plan of Foundation Method being based on N-Value in the Soft-Ground (연약지반에 있어 N치에 의한 기초공법 대책연구)

  • Lee, Y.H.;Lee, D.M.
    • Journal of Korean Port Research
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    • v.10 no.2
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    • pp.69-90
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    • 1996
  • This study is related to save the bearing capacity from using Meyerhof formula namely, static mechanics formula with the S.P.T(N value) of the soft ground and is to choose the soft ground improvement method by the using of total load for the proper method of the pile foundation and then to design the most suitable pile foundation to fit the actual circumstance. The purpose of this study is calculating the diameter of the pile foundation by static mechanics formula and introducing the optimum design condition from the result of the bearing capacity for using N value of the S.P.T obtained from the deep soft ground about the piles such as P.H.C pile, pipe and cast-in-place pile of big diameter, etc. As above-mentioned, it is considered that the use of P.H.C pile or pipe pile is advisable on the synthetical investigation and that the selection of cast-in-place pile method is desirable in terms of the constructive safety and durability.

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Hardware design for SNR estimation of QAM modulation systems (QAM 변조 방식에 대한 SNR 추정을 위한 하드웨어 구현)

  • Jung, Man-Ho;Song, Sang-Seob;Kim, Soo-Young
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.77-78
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    • 2006
  • This paper presents a signal quality estimation technique for QAM modulation systems. By making a LUT(Look-up table) putting the number of N enough, we can derive estimated SNR from LUT even though N is small. That is so called MOTM algorithm. In 16-QAM, the distance dada, between adjacent symbols is always invariable, so absolute value of R(the amplitude of signal) minus dada has a always same signal distribution value. This value does not form a Gaussian shape but, by making a little bit correction, we can make this symmetrical. So, from the received symbol value, by using LUT we can easily derive the estimated SNR. By considering this, we introduce a signal quality estimation technique for QAM schemes. This proposed method can be applicable to high order modulation schemes and wide range of signal to noise ratio.

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Polynomial Time Algorithm for Multi-Beam SS/TDMA Satellite Communications Scheduling Problem with Frequency-Hopping Ground Stations

  • Lee, Sang-Un
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.7
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    • pp.33-40
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    • 2015
  • The time slot assignment problem (TSAP) or Satellite Communications scheduling problem (SCSP) for a satellite performs n×nn×n ground station data traffic switching has been known NP-hard problem. This paper suggests O(n2)O(n2) time complexity algorithm for TSAP of a satellite that performs n2×n2n2×n2 ground station data traffic switching. This problem is more difficult than n×nn×n TSAP as NP-hard problem. Firstly, we compute the average traffic for n-transponder's basic coverage zone and applies ground station exchange method that swap the ground stations until all of the transponders have a average value as possible. Nextly, we transform the D matrix to DLBDLB traffic matrix that sum of rows and columns all of transponders have LB. Finally, we select the maximum traffic of row and column in DLBDLB, then decide the duration of kth switch mode to minimum traffic from selected values. The proposed algorithm can be get the optimal solution for experimental data.

Generalization of Galois Linear Feedback Register (갈로이 선형 궤환 레지스터의 일반화)

  • Park Chang-Soo;Cho Gyeong-Yeon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.43 no.1 s.307
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    • pp.1-8
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    • 2006
  • This thesis proposes Arithmetic Shift Register(ASR) which can be used as pseudo random number generator. Arithmetic Shift. Register is defined as progression that multiplies random number D , not 0 or 1 at initial value which is not 0, and it is represented as ASR-D in this thesis. Irreducible polynomial that t which makes Dk=1 satisfies uniquely as t=2n1 over. GF(2n) is the characteristic polynomial of ASR-D , and the cycle of Arithmetic Shift Register has maximum cycle as 2n1. Galois Linear Feedback Shift Register corresponds to ASR-2-1. Therefore, Arithmetic Shift Register proposed in this thesis generalizes Galois Linear Feedback Shift Register. Linear complexity of ASR-D overGF(2n) is nLCn2+n2 and in comparison with existing Linear Feedback Shift Register stability is high. The Software embodiment of arithmetic shift register proposed in this thesis is efficient than that of existing Linear Shift Register and hardware complexity is equal. Arithmetic shift register proposed in this thesis can be used widely in various fields such as cipher, error correcting codes, Monte Carlo integral, and data communication etc along with existing linear shift register.

Response Analysis of the NE213-PSD System for Neutron Energy Spectreum Measurement (중성자 에너지 측정을 위한 NE213-PSD 장치의 감응 분석)

  • Lee, Kyung-Ju
    • Analytical Science and Technology
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    • v.5 no.4
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    • pp.367-372
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    • 1992
  • In order to measure the energy spectrum of a radioactive neutron source, the pulse shape discrimination (PSD) system with organic scintillator, NE-213, was characterized by using some of the gamma ray sources and neutron source, Am-Be. The figure of merit of the rise time spectrum of AmBe source measured by this system was about 1.13. This value agrees well with the value of 1.3 which is measured for monoenergetic source, 12C(d,n)13N. The results of present experiment for performance test of NE213-PSD system will provide the useful technique to measure the spectrum of neutron-gamma mixed field and to establish the neutron energy spectrum and flux density standards.

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A study on the settlement of earth dam by the changes of the density (흙댐의 밀도변화에 의한 압밀침하에 대한 연구)

  • 윤충섭
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.28 no.3
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    • pp.89-98
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    • 1986
  • This study was carried out for the settlement and camber of earth dam by the changes of the density. The testing material was taken five kinds of Soil used as banking material and it was compacted by 100, 95, 90, 85 and 80% compaction degree. The results of the settlement of earth dam whose height ranges from 10m to 50m are as follows. 1.The more the fine particle (n) increases, the higher the liquid limit (WL) and the lower the dry density (rd) becomes as follows; rd=2. 22-0. 0052n (gr/cm3) rd=2. 394-0. 0164WL rd=2. 185-(5. 8n-2. 5WL)X10-3 2. The higher the optimum moisture content (Wo) becomes, the lower the density becomes as follows; rt,=2. 68-0. 028Wo rd=2. 578-0. 04Wo 3. 3.Most of the consolidation occurs immediately by loading and the more the fine particle increases, the lower the coefficient of consolidation becomes. 4.The more the fine particle increases and lower the compaction degree (D) becomes,the lower the pre-consolidation load (Pc) becomes but on the contrary the compression index (Cc) becomes higher. Those equation is as follows. Pc=3. 32-(4. 3n-3. 0D) X10-2 (kg/cm2) Cc=0. 41+(1. 33n-4. 44D) X10-3 5.The more the consolidation load (P) increases, the lower the coefficient of volume change (mv) becomes with mv=ap-b, the higher the consolidation ratio (u) becomes with U= (0. 6~1. 35)PO.4 6.The more the fine particle (n) increases, the more the settlement of dam occurs with U=anb and 60-80% of the settlement occurs under construction. 7.The camber of dam has higher value in condition that has more fine particle, poorer compaction and higher height of dam. In the dam construction about twice value of table 7 is required for dam safety.

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Four-Valued Cross-Correlation Function between Two Maximal Linear Recursive Sequences (최대 주기의 두 선형 순환 수열 사이의 4개의 값을 갖는 상호상관함수)

  • Choi, Un-Sook;Kim, Sung-Jin;Kim, Han-Doo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.6
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    • pp.1369-1375
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    • 2012
  • One of important problems in the theory of sequences is to determine the values and number of occurrences of each value taken on by the cross-correlation. In this paper, we find the values and the number of occurrences of each value of cross-correlation between an m-sequence u(t) of period 2n1 and its decimation u(dt)(0t2n2) where n=2m, 2s|m and d=(22m+22s+12m+s+11)/(2s1). Also we show that a family of decimations leads to a four-valued cross-correlation.

A Dialectical Study of the Book Selection Theory (도서선택론의 변증법적 연구)

  • Yun Hee-Yun
    • Journal of the Korean Society for Library and Information Science
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    • v.29
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    • pp.173-204
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    • 1995
  • The purpose of this study is to promote understanding of the book selection theory by researching dialectically of its development process centering on the BSTv(value theory) and BSTd(demand theory). The results of this study are summarized as follows 1. In the period of enlightenment and education, the book selection theory of public libraries was the thesis state of BSTv(d). 2. Antithesis state of BSTv(d), that is, BSTd was raised to real central theory of book selection in the early 20th century. 3. In the 1930-40's, BSTv and BSTd were transformed into balance state or coexistence relations(BSTb [v(d)d(v)]. 4. After World War II, BSTn(library needs theory) and BSTo(library objective theory) were evoked, and opposed to the existing selection theories. Now, they are developing into BSTbl[n(d)o(v)orn(d)v(o)].

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