352 research outputs found
A Novel Construction of Multi-group Decodable Space-Time Block Codes
Complex Orthogonal Design (COD) codes are known to have the lowest detection
complexity among Space-Time Block Codes (STBCs). However, the rate of square
COD codes decreases exponentially with the number of transmit antennas. The
Quasi-Orthogonal Design (QOD) codes emerged to provide a compromise between
rate and complexity as they offer higher rates compared to COD codes at the
expense of an increase of decoding complexity through partially relaxing the
orthogonality conditions. The QOD codes were then generalized with the so
called g-symbol and g-group decodable STBCs where the number of orthogonal
groups of symbols is no longer restricted to two as in the QOD case. However,
the adopted approach for the construction of such codes is based on sufficient
but not necessary conditions which may limit the achievable rates for any
number of orthogonal groups. In this paper, we limit ourselves to the case of
Unitary Weight (UW)-g-group decodable STBCs for 2^a transmit antennas where the
weight matrices are required to be single thread matrices with non-zero entries
in {1,-1,j,-j} and address the problem of finding the highest achievable rate
for any number of orthogonal groups. This special type of weight matrices
guarantees full symbol-wise diversity and subsumes a wide range of existing
codes in the literature. We show that in this case an exhaustive search can be
applied to find the maximum achievable rates for UW-g-group decodable STBCs
with g>1. For this purpose, we extend our previously proposed approach for
constructing UW-2-group decodable STBCs based on necessary and sufficient
conditions to the case of UW-g-group decodable STBCs in a recursive manner.Comment: 12 pages, and 5 tables, accepted for publication in IEEE transactions
on communication
A New Low-Complexity Decodable Rate-1 Full-Diversity 4 x 4 STBC with Nonvanishing Determinants
Space-time coding techniques have become common-place in wireless
communication standards as they provide an effective way to mitigate the fading
phenomena inherent in wireless channels. However, the use of Space-Time Block
Codes (STBCs) increases significantly the optimal detection complexity at the
receiver unless the low complexity decodability property is taken into
consideration in the STBC design. In this letter we propose a new
low-complexity decodable rate-1 full-diversity 4 x 4 STBC. We provide an
analytical proof that the proposed code has the Non-Vanishing-Determinant (NVD)
property, a property that can be exploited through the use of adaptive
modulation which changes the transmission rate according to the wireless
channel quality. We compare the proposed code to existing low-complexity
decodable rate-1 full-diversity 4 x 4 STBCs in terms of performance over
quasi-static Rayleigh fading channels, detection complexity and Peak-to-Average
Power Ratio (PAPR). Our code is found to provide the best performance and the
smallest PAPR which is that of the used QAM constellation at the expense of a
slight increase in detection complexity w.r.t. certain previous codes but this
will only penalize the proposed code for high-order QAM constellations.Comment: 5 pages, 3 figures, and 1 table; IEEE Transactions on Wireless
Communications, Vol. 10, No. 8, AUGUST 201
Assessing Chinas Development Cooperation Policy Towards African Countries: the case of Egypt
ํ์๋
ผ๋ฌธ (์์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ตญ์ ๋ํ์ ๊ตญ์ ํ๊ณผ(๊ตญ์ ์ง์ญํ์ ๊ณต), 2020. 8. ์ ์๋ก.๋ณธ ์ฐ๊ตฌ๋ ์ํ๋ฆฌ์นด์ ๋ํ ์ค๊ตญ์ ๊ฐ๋ฐํ๋ ฅ ์ ์ฑ
์ด ์์๊ฐ ๋ฐ ๋ค์๊ฐ ํ๋ ฅ์ ํตํด ์ด๋ฃจ์ด์ง๋ฉด์ FOCAC๊ฐ ์ค๋ฆฝ๋ ์ดํ๋ก ์ด๋ป๊ฒ ๋ณํํ๋์ง, ํนํ ์ด์งํธ์ ๋ํ ์ ์ฑ
์ ๋ณํ๋ฅผ ์์๋ณด๊ธฐ ์ํ ๊ฒ์ด๋ค. ์ด๋ฅผ ์ํด์๋ ์ง๋ฌธ ๋ช ๊ฐ์ง๋ฅผ ๋์ ธ์ผ ํ๋ค. ์ํ๋ฆฌ์นด์ ๋ํ ์ค๊ตญ์ ๋ฐ์ ํ๋ ฅ์ด ์ผ๋ง๋งํผ ํน๋ณํ๊ฐ? ๋์๊ฐ, ์ค๊ตญ์ ์ํ๋ฆฌ์นด์ ์ด๋ ์ ๋๊น์ง ๊ด์ฌ์ด ์์ผ๋ฉฐ, ์ ๊ทธ๋ฐ๊ฐ? ์ํ๋ฆฌ์นด ๊ตญ๊ฐ๋ค์ ๋ํ ์ค๊ตญ์ ๋ฐ์ ์ ์ฑ
์ ๋ฌด์์ธ๊ฐ? ์ค๊ตญ์ด ์ํ๋ฆฌ์นด ๋ด ์ธ๊ณ ์ํ๊ณผ ์ด๋ป๊ฒ ํ๋ ฅํ๋๊ฐ? ์ํ๋ฆฌ์นด ๊ตญ๊ฐ๋ค์ ๋๋ฅ ๋ด ์ค๊ตญ์ ์กด์ฌ, ๊ทธ๋ฆฌ๊ณ ๊ทธ ๋ฏธ๋๋ฅผ ์ด๋ป๊ฒ ๋ณด๋๊ฐ? ๋ํ, ์ค๊ตญ์ ์๋ก์ด ๊ตญ์ ๊ธ์ต๊ธฐ๊ตฌ๋ค์ ์ํ๋ฆฌ์นด์์ ์ง์๊ฐ๋ฅํ ๋ฐ์ ์ ์ด๋ฃฐ ์ ์๋๊ฐ?
์ฐ๊ตฌ ๊ฒฐ๊ณผ์ ๋ฐ๋ฅด๋ฉด ์ค๊ตญ์ ๊ฐ๋ฐ ํ๋ ฅ์ ๋ค๋ฅธ ๊ณต์ฌ๊ตญ๊ณผ๋ ๋ค๋ฅด๋ค. ์ค๊ตญ์ ๋ค๋ฅธ ๊ณต์ฌ๊ตญ์ด ์ํ๋ฆฌ์นด ๊ตญ๊ฐ๋ค์ ์ ๊ณตํ ์์กฐ์ ์์ด๋ ์ ํ, ๊ทธ๋ฆฌ๊ณ ์ฐ์ ์์์ ์ฃผ์๋ฅผ ๊ธฐ์ธ์ด์ง ์์๋ค. ๋ํ, ์ํ๋ฆฌ์นด์ ๋ํ ์ค๊ตญ์ ๊ด์ฌ์ ๋จ์ํ ์์์ฌ ๊ตฌ๋งค๋ฅผ ๋์ด์๊ณ ์๋ค. ์ค๊ตญ์ ์ํ๋ฆฌ์นด์ ์ต๋ ๊ณต์ฌ๊ตญ์ด ๋๊ฒ ๋ค๋ ์ฝ์์ ํ๊ณ ๊ฒฐ๊ตญ ์ํ๋ฆฌ์นด์ ๊ฐ์ฅ ํฐ ๊ณต์ฌ๊ตญ์ด ๋์์ผ๋ฉฐ, 2009~2012๋
๊ณผ 2015๋
๋ฐ 2018๋
์ฌ์ด์ ์ํ๋ฆฌ์นด์ ๋ํ ์ง์์ ๋ ๋ฐฐ๋ก ๋๋ ธ๋ค.This study is to figure out the change of Chinas Development Cooperation policy toward Africa Since set up FOCAC, in particular, Egypt, through bilateral and multilateral cooperation. To address some pertinent questions to what extent Chinas developmental cooperation toward Africa is unique? Furthermore, how far is China interested in Africa, and why? What is the Chinese Policy for development toward African countries? How China cooperate with the World Bank in Africa? How do African governments view China's presence on the continent and the future? Moreover, Does Chinas New International Financing Institutions can achieve Sustainable development in African countries?
The study result showed that China's development cooperation is different from other donors. China did not pay attention to the amount or types or priorities of aid given to African countries by other donors. In addition to China, interest in Africa goes beyond the procurement of raw materials. China promises to be the largest donor to Africa, and they become the most significant donor eventually to Africa, and they double its aid to African countries between 2009 - 2012, and in 2015 & 2018.CHAPTER I: Introduction 1
1.1 Background 1
1.2 Significance of the study 3
1.3 Purpose of research 3
1.4 Hypothesis and research questions 3
1.5 Scope of the research 4
1.6 Organization of the Study 4
CHAPTER II: LITERATURE REVIEW AND METHODOLOGY 6
2.1 Literature review 6
2.2 Methodology 10
CHAPTER III: China's development cooperation policy toward Africa 12
3.1 Background 12
3.1.1 A brief history of Africa-China relations 12
3.2 The framework of China Development Cooperation 13
3.2.1 China Development Cooperation instruments 13
3.2.1.1 First: Multilateral cooperation 13
3.2.1.2 Second: bilateral cooperation 14
3.2.1.3 Fourth: China International Development Cooperation Agency (CIDCA) 17
3.3 Analysis of the development cooperation instruments in African countries 18
3.3.1 China's Development Cooperation and Africa 18
3.3.2 Chinese infrastructure investment and the effectiveness of Chinese aid in Africa: 20
3.3.3 China Loans to Africa 25
3.3.4 China Africa Trade 29
3.3.5 China FDI to Africa 29
3.3.6 A brief comparison between Japan-China ODA to Africa 30
3.3.7 China Multilateral Cooperation and World Bank Cooperation 31
3.3.8 How China Is Take Advantage of Multilateral cooperation 32
CHAPTER IV: Case study China's Development Cooperation in Egypt 40
4.1 Egypt and China 40
4.2 China Aid to Egypt 41
4.3 Trade between China and Egypt 44
4.1 China FDI to Egypt. 45
4.5 The Case of Egypt: Project is "Remote Education System Upgrade. 47
CHAPTER V: Conclusion & Policy Recommendations 50
5.1 Policy Recommendation for a Better Cooperation 50
5.1.1 To China 50
5.1.2 To Egypt and African Countries 50
5.2 Conclusion 53
5.2.1 Limitations 53
5.2.2 Conclusion 53
REFERENCES 56
APPENDIX. 61
(Korean Abstract) 68Maste
A New Low-Complexity Decodable Rate-5/4 STBC for Four Transmit Antennas with Nonvanishing Determinants
The use of Space-Time Block Codes (STBCs) increases significantly the optimal
detection complexity at the receiver unless the low-complexity decodability
property is taken into consideration in the STBC design. In this paper we
propose a new low-complexity decodable rate-5/4 full-diversity 4 x 4 STBC. We
provide an analytical proof that the proposed code has the
Non-Vanishing-Determinant (NVD) property, a property that can be exploited
through the use of adaptive modulation which changes the transmission rate
according to the wireless channel quality. We compare the proposed code to the
best existing low-complexity decodable rate-5/4 full-diversity 4 x 4 STBC in
terms of performance over quasi-static Rayleigh fading channels, worst- case
complexity, average complexity, and Peak-to-Average Power Ratio (PAPR). Our
code is found to provide better performance, lower average decoding complexity,
and lower PAPR at the expense of a slight increase in worst-case decoding
complexity.Comment: 5 pages, 2 figures and 1 table; IEEE Global Telecommunications
Conference (GLOBECOM 2011), 201
Energy-Efficient Cooperative Protocols for Full-Duplex Relay Channels
In this work, energy-efficient cooperative protocols are studied for
full-duplex relaying (FDR) with loopback interference. In these protocols,
relay assistance is only sought under certain conditions on the different link
outages to ensure effective cooperation. Recently, an energy-efficient
selective decode-and-forward protocol was proposed for FDR, and was shown to
outperform existing schemes in terms of outage. Here, we propose an incremental
selective decode-and-forward protocol that offers additional power savings,
while keeping the same outage performance. We compare the performance of the
two protocols in terms of the end-to-end signal-to-noise ratio cumulative
distribution function via closed-form expressions. Finally, we corroborate our
theoretical results with simulation, and show the relative relay power savings
in comparison to non-selective cooperation in which the relay cooperates
regardless of channel conditions
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A New Family of Low-Complexity Decodable STBCs for Four Transmit Antennas
In this paper we propose a new construction method for rate-1
Fast-Group-Decodable (FGD) Space-Time-Block Codes (STBC)s for 2^a transmit
antennas. We focus on the case of a=2 and we show that the new FGD rate-1 code
has the lowest worst-case decoding complexity among existing comparable STBCs.
The coding gain of the new rate-1 code is then optimized through constellation
stretching and proved to be constant irrespective of the underlying QAM
constellation prior to normalization. In a second step, we propose a new rate-2
STBC that multiplexes two of our rate-1 codes by the means of a unitary matrix.
A compromise between rate and complexity is then obtained through puncturing
our rate-2 code giving rise to a new rate-3/2 code. The proposed codes are
compared to existing codes in the literature and simulation results show that
our rate-3/2 code has a lower average decoding complexity while our rate-2 code
maintains its lower average decoding complexity in the low SNR region at the
expense of a small performance loss.Comment: 5 pages, 4 figures and 1 table. Accepted for publication in IEEE
International Conference on Communications (ICC 2012), 201
B738: Costs and Returns in Lowbush Blueberry Production in Maine, 1974 Crop
Blueberry production is primarily a part time enterprise with a wide variation in acreages per grower and a modest investment per acre.
Blueberry growers recovered cash costs and most of the variable costs of producing and harvesting the 1974 crop. For a competitive return on investment and a modest wage, the average grower would have had to receive 35 cents rather than 20 cents per pound, considering the yields obtained in 1974. To be reasonably assured of adequate returns, a grower should achieve yields of over 1,000 pounds per acre.https://digitalcommons.library.umaine.edu/aes_bulletin/1086/thumbnail.jp
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