438 research outputs found

    Non-classical properties and generation schemes of superposition of multiple-photon-added two-mode squeezed vacuum state

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    In this paper, we study some non-classical properties and propose the generation schemes of the superposition of multiple-photon-added two-mode squeezed vacuum state (SMPA-TMSVS). Based on the   Wigner function, we clarify that this state is a non-Gaussian state, while the original two-mode squeezed vacuum state (TMSVS) is a Gaussian state. Besides, the SMPA-TMSVS is sum squeezing, as well as difference squeezing. In particular, the manifestation of the sum squeezing and the difference squeezing in the SMPA-TMSVS becomes more pronounced when increasing parameters r and e. In addition, by exploiting the schemes of photon-added superposition in the usual order, we give some schemes that the SMPA-TMSVS can be generated with the higher-order photon-added superposition by using some optical devices

    A New Linear Printed Vivaldi Antenna Array with Low Side Lobe Level and High Gain for the Band 3.5 GHz

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    This paper proposes a new design of low sidelobe level (SLL) and high gain linear printed Vivaldi antenna array. The array composes of two parts, which are a linear Vivaldi antenna array and a back reflector. The array consists of 10 single Vivaldi antennas and a series-fed network, those are based on Roger RO4003C substrate (ε = 3.55) with the dimension of 140 x 450 x 1.524 mm3. A new Bat algorithm with the amplitude-only control technique has been applied to optimize the output coefficients of the series-fed network for gaining a low SLL. The simulation results indicate that the proposed antenna provides a low SLL of -29.2 dB in E-plane with a high gain of 16.5 dBi at the frequency of 3500 MHz. A prototype of the proposed antenna array has been fabricated. The measured data has a good agreement with the simulated data

    Phân tích chi phí-lợi ích của đồng đốt sinh khối với than: Trường hợp nhà máy nhiệt điện Ninh Bình

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    National audienceĐồng đốt sinh khối với than là công nghệ tận dụng sinh khối để phát điện với mức chi phí thấp hơn rấtnhiều so với việc xây dựng nhà máy điện sinh khối. Đồng đốt giúp giảm bớt tác động của nhiệt điện thanđến kinh tế, môi trường và xã hội. Việt Nam có tiềm năng phát triển công nghệ này do có tiềm năng lớn vềsinh khối cũng như do Việt Nam sẽ tiếp tục phát triển các nhà máy nhiệt điện than trong vòng 2 thập kỷ tớitheo như Quy hoạch điện mới nhất.Trong số các công nghệ đồng đốt, đồng đốt trực tiếp là công nghệ phù hợp nhất đối với điều kiện Việt Namhiện nay. Mặc dù tỉ lệ đồng đốt thấp nhưng chi phí chuyển đối thấp nhất và có thể tận dụng hầu hết cácloại sinh khối. Việt Nam có nguồn sinh khối dồi dào, đặc biệt là nguồn phụ phẩm, phế phẩm nông nghiệp.Đây là các nguồn sinh khối nên được cân nhắc sử dụng trước tiên cho đồng đốt. Viên nén sinh khối cũnglà một lựa chọn tốt cho đồng đốt xét về các đặc tính kỹ thuật cũng như nguồn cung trong nước. Tuy nhiêngiá cả của viên nén chưa thực sự cạnh tranh được với than cũng như với nguồn phụ phẩm phế phẩm nôngnghiệp.Hiệu quả về mặt kinh tế của đồng đốt sinh khối với than sẽ cao hơn tại các nhà máy có các điều kiện nhưsau: sử dụng lò đốt than, tiếp cận được với nguồn cung sinh khối ổn định và có mức giá cạnh tranh, có giáthan cao, có các điều kiện ưu tiên về thị trường cũng như cơ chế đối với sử dụng năng lượng tái tạo vàgiảm rác thải. Việt Nam nên bắt đầu thí điểm với các nhà máy nhiệt điện than nằm tại các vùng có trữlượng sinh khối cao, thuận lợi cho việc thu gom và vận chuyển sinh khối, sử dụng than nhập khẩu có nguồncung than không ổn định và giá than cao như Vĩnh Tân 2, Duyên Hải 1, Long Phước 1...; hoặc các nhàmáy sắp hết thời gian khấu hao như Ninh Bình, Uông Bí hay Phả Lại 1 để tận dụng cơ sở hạ tầng sẵn có.Phân tích trường hợp đồng đốt 5% rơm với than tại nhà máy nhiệt điện Ninh Bình cho thấy đồng đốt đãmang lại hiệu quả kinh tế cho nhà máy trong điều kiện không có cơ chế chính sách hỗ trợ cho đồng đốtcũng như chưa có thị trường cacbon và doanh thu từ bán tro xỉ than. Mặt khác, lợi ích mà đồng đốt đemlại cho xã hội cũng như môi trường là rất đáng kể, đặc biệt là đối với người nông dân và sức khỏe cộngđồng. Các lợi ích này, nếu có cơ chế chia sẽ hợp lý sẽ có thể hỗ trợ cho nhà máy áp dụng đồng đốt đạthiệu quả cao hơn về mặt kinh tế

    Socio-economic impacts of co-firing in Vietnam: The case of Ninh Binh Coal Power Plant

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    International audienceCo-firing biomass with coal is a relatively low-cost technology to utilize biomass for electricity production compared to dedicated biomass power plant. Co-firing could help to reduce the negative impact of coal power plants to economy, environment and society. Vietnam has potential to develop co-firing base on the abundant of biomass resources and because Vietnam will continue to build more coal-fired power plant in the next 2 decades as stated in the latest National Power Development Plan.Among the co-firing technologies, direct co-firing is the most suitable for Vietnam context. Despite of low biomass ratio, direct co-firing offers low investment cost and could utilize most of the biomass feedstock. Vietnam has huge biomass potential, especially the agriculture and forestry residues. These biomasses should be considered first as feedstock for co-firing. Biomass pellets is also a good choice in term of technical features and local supply. However, the price of pellets is not yet competitive with coal or agricultural residues.Economic benefit of co-firing would be higher in the plants that has following features: assess to stable biomass supply, biomass price competitive with coal, incentives and support in term of market for renewable energy utilization and waste reduction. Vietnam should start experimenting co-firing in the coal power plants that located in the area where biomass resource is available, easy to collect and deliver to the plant, using imported coal such as Vinh Tan 2, Duyen Hai 1, Long Phuoc 1…; or the plants that are soon or already depreciated such as Ninh Binh, Uong Bi or Pha Lai to utilize the existing infrastructures.The case study of co-firing 5% rice straw with coal in Ninh Binh Coal Power Plant shows that co-firing could bring benefit to the plant owner in the condition that lack supporting mechanism for co-firing as well as with the absent of carbon credit. Farmers and workers that work in biomass supply chain also benefit from co-firing, especially farmers. In addition, co-firing provide significant positive externalities, in which the most notable is health benefit from reducing air-borne pollutants. Greenhouse gas emissions reduction adds a small part to the overall benefit of co-firing

    ROBUST DYNAMIC ID-BASED REMOTE MUTUAL AUTHENTICATION SCHEME

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    Dynamic ID based authentication scheme is more and more important in insecure wireless environment and system. Two of kinds of attack that authentication schemes must resist are stealing identity and reflection attack which is a potential way of attacking a challenge- response authentication system using the same protocol in both direc­tions. It must be guaranteed to prevent attackers from reusing informa­tion from authentication phase and the scheme of Yoon and Yoo satisfies those requirements. However, their scheme can not resist insider and impersonation attack by using lost or stolen smart card. In this paper, we demonstrate that Yoon and Yoo’s scheme is still vulnerable to those attacks. Then, we present an improvement to their scheme in order to isolate such problems

    Beyond Domain Adaptation: Unseen Domain Encapsulation via Universal Non-volume Preserving Models

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    Recognition across domains has recently become an active topic in the research community. However, it has been largely overlooked in the problem of recognition in new unseen domains. Under this condition, the delivered deep network models are unable to be updated, adapted or fine-tuned. Therefore, recent deep learning techniques, such as: domain adaptation, feature transferring, and fine-tuning, cannot be applied. This paper presents a novel Universal Non-volume Preserving approach to the problem of domain generalization in the context of deep learning. The proposed method can be easily incorporated with any other ConvNet framework within an end-to-end deep network design to improve the performance. On digit recognition, we benchmark on four popular digit recognition databases, i.e. MNIST, USPS, SVHN and MNIST-M. The proposed method is also experimented on face recognition on Extended Yale-B, CMU-PIE and CMU-MPIE databases and compared against other the state-of-the-art methods. In the problem of pedestrian detection, we empirically observe that the proposed method learns models that improve performance across a priori unknown data distributions

    Vietnam’s Security Challenges: Priorities, Policy Implications and Prospects for Regional Cooperation

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    The historic end of the Cold War and the rising tide of globalization have significantly changed the nature of threats and security discourses in Asia. There is a notable shift of attention from military power as the core determinant of national security to several non-traditional sectors with a much enhanced role of economic, political, and societal forces. Non-traditional security issues—such as climate change, natural disasters, transnational crimes, and terrorism—require both policymakers and military strategists to deal with security threats in a more comprehensive manner. Increasing interdependence among states also magnifies the impacts of these threats, urging Asian countries to forge regional cooperation in multilateral forums such as ASEAN, EAS, APEC, and ARF. Though these efforts are commendable, their effectiveness in tackling such a wide canvass of threats is still open to questio
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