667 research outputs found

    Forward Private Searchable Symmetric Encryption with Optimized I/O Efficiency

    Get PDF
    Recently, several practical attacks raised serious concerns over the security of searchable encryption. The attacks have brought emphasis on forward privacy, which is the key concept behind solutions to the adaptive leakage-exploiting attacks, and will very likely to become mandatory in the design of new searchable encryption schemes. For a long time, forward privacy implies inefficiency and thus most existing searchable encryption schemes do not support it. Very recently, Bost (CCS 2016) showed that forward privacy can be obtained without inducing a large communication overhead. However, Bost's scheme is constructed with a relatively inefficient public key cryptographic primitive, and has a poor I/O performance. Both of the deficiencies significantly hinder the practical efficiency of the scheme, and prevent it from scaling to large data settings. To address the problems, we first present FAST, which achieves forward privacy and the same communication efficiency as Bost's scheme, but uses only symmetric cryptographic primitives. We then present FASTIO, which retains all good properties of FAST, and further improves I/O efficiency. We implemented the two schemes and compared their performance with Bost's scheme. The experiment results show that both our schemes are highly efficient, and FASTIO achieves a much better scalability due to its optimized I/O

    KNOWLEDGE MANAGEMENT CAPABILITY AND FIRM PERFORMANCE: THE MEDIATING ROLE OF ORGANIZATIONAL AGILITY

    Get PDF
    Implementing knowledge management capability (KMC) effectively is becoming an important strategic issue for organizational success. However, our understanding about the underlying mechanism of KMC on firm performance is still limited. Based on the dynamic capabilities perspective, this study tries to explore how KMC (i.e., exploration KMC and exploitation KMC) affects firm performance through the mediating role of operational adjustment agility and market capitalizing agility. Survey data from 211 firms indicate that both operational adjustment agility and market capitalizing agility can fully mediate the influence of KMC on firm performance. In addition, the relationship intensions of these two KMC on organizational agility are distinguishing. We conclude with implications and limitations for future research

    Turbo Coded and Cooperative Network Coded Non-Coherent Soft-Decision Star-QAM Dispensing with Channel Estimation

    No full text
    Star Quadrature Amplitude Modulation (Star-QAM) is a non-coherent detection aided scheme ideal for low-complexity wireless transceivers. In this contribution, we first derive soft-decision aided StQAM symbol-to-bit demapping combined with iterative detection aided Turbo Coding (TC). Then we combine this physical layer design with network coding (NC) and quantify the attainable coding gain. It is shown that the proposed 16-level Star-QAM (16-StQAM) based TC scheme is capable of achieving a coding gain of about 1.5~dB over the TC aided 16-level Differential Phase-Shift Keying (16DPSK) benchmark scheme at a BER of 10-5. The 16-StQAM based TC assisted scheme is capable of offering another 1.2~dB coding gain, when it is employed in a 'butterfly' topology network arrangement. When the source and relay nodes are allowed to transmit at different power levels, the two-hop 16-StQAM based TC aided NC scheme outperforms the single-hop 16-StQAM based TC scheme by approximately 2.2~dB

    A Multi-turn Machine Reading Comprehension Framework with Rethink Mechanism for Emotion-Cause Pair Extraction

    Full text link
    Emotion-cause pair extraction (ECPE) is an emerging task in emotion cause analysis, which extracts potential emotion-cause pairs from an emotional document. Most recent studies use end-to-end methods to tackle the ECPE task. However, these methods either suffer from a label sparsity problem or fail to model complicated relations between emotions and causes. Furthermore, they all do not consider explicit semantic information of clauses. To this end, we transform the ECPE task into a document-level machine reading comprehension (MRC) task and propose a Multi-turn MRC framework with Rethink mechanism (MM-R). Our framework can model complicated relations between emotions and causes while avoiding generating the pairing matrix (the leading cause of the label sparsity problem). Besides, the multi-turn structure can fuse explicit semantic information flow between emotions and causes. Extensive experiments on the benchmark emotion cause corpus demonstrate the effectiveness of our proposed framework, which outperforms existing state-of-the-art methods.Comment: Accepted to COLING 202

    岩石伝説の身体性に関する一考察  ―『日本伝説大系』と『日本の伝説』を中心に―

    Get PDF
    本稿では全国の各地の伝説を所収した『日本伝説大系』と『日本の伝説』をテキストに、身体に関する岩石伝説に着目し、その特徴と背後にある信仰などについて考察したい。本稿では特に身体的な特徴の表れる血の出る岩石、声の出る岩石、成長する岩石、米を食べる岩石の伝説を取り上げ、それぞれの岩石の特徴を分析した。まず、血の出る岩石伝説において、岩石の居場所は境であり、割るまたは悟ることによって不思議な色の血が噴き出した。また同時に、割る人は死ぬか発狂するかなどの罰を受けた。血が出ることによって、岩石への畏敬の気持ちを持ち、依り代またはタマが宿る岩石を神聖視したと言える。次に、声の出る岩石伝説は主に泣く岩石伝説と話す岩石伝説に分けられる。人間の言葉、動物の声、鬼の泣き声などの言語で元の場所に帰りたい、異変の予告などを伝えた。米を食べる岩石伝説では岩石が生きものように食糧を食べる。また、成長する岩石伝説は大きくなる岩石と小石を生む岩石の伝説に分けられ、岩石は成長力と生殖力を持っているとみなされていたこと明らかとなった。血が出る岩石、声を発する岩石、米を食べる岩石と成長する岩石という4つの身体性には、共通の特徴も見られる。まず、岩石の活動時間が夜であること。そして、岩石の言葉は人間に通じるものだけではなく、動物の鳴き声などの岩石特有の言語も発する。そのほかに、岩石の成長する速さは百年、千年かかる。さらに割られたら死ぬ岩石もある。一つの岩石がすべての身体的特徴を備えているわけではないが、小石を生む岩石があり、成長する岩石があり、さらに死ぬ岩石があり、人間の誕生から死までの身体的特徴を備え各種の岩石伝説がある。岩石が身体性を持つのは、岩石が神の依り代だけではなく、岩石そのものにもタマがあると考えられてきたからだ。また、アニミズムの考え方によって、石、木などのあらゆる自然物は人間と同じく、霊魂がやどっていると考えられてきた。また、岩石は人間の一生とも緊密に関わり、通過儀礼にも大きな役割を果たしてきた。このような岩石の特徴が、身体性を持った数多くの多様な伝説を生み出してきたと考えられる。This paper discusses Japanese legends concerning rocks that involve the human body with reference to the Nihon Densetsu Taikei published by Mizuumi Shobo and Nihon-no-Densetsu published by Kadokawa Shoten. The author explores the characteristics of rock legends that involve the human body, as well as the human beliefs behind them.According to the previous research, there are a number of rock legends featuring the human body, and the author categorized them into four types by the characteristics of rocks: bleeding rocks, vocalizing rocks, rice-eating rocks, and growing rocks. In the first type, rocks are observed in a deserted place, and the rocks bleed when they are smashed or men achieve enlightenment. In addition, the legends state that the blood color of the rocks were varied and not only to red, but sometimes also included purple or black. The bleeding rock legend indicates that the rock is not just an epitome of a godly religion, but an animate being. With regard to the second type, the rocks can be further subcategorized into talking rock legends and weeping rocks. The former can express their feelings, such as wanting to return to where they used to be, or predict disaster through human language, animal voices, or the crying sound of ogres. Third are the rice-eating rock legends. These rocks may be interpreted as being alive and eating like creatures. Last, growing rocks can be divided into rocks that increase in size and child-bearing rocks. Some grow and give birth to pebbles.Bleeding, vocalizing, rice-eating and growing are different attributes of human bodylore, but they all share something in common. First, rocks that bleed, talk or eat rice are active at night. The language of rocks that can vocalize is not only human language but also rock-specific languages that are similar to animal voices. In addition, in some legends rocks grow, but at a speed much slower than that of humans, taking 100 or 1,000 years. Nonetheless, it seems that they are born, grow and die like human beings.The author regards that there are three reasons for the physicality of rocks. First, a rock is not just an epitome of a godly religion, but an animate being. Next, in the animistic world, people believed that like rocks, plants and all elements of nature have souls. Last, rocks were believed to be closely related to the process of life. Such rock characteristics may have been one of the factors that produced many diverse legends involving the body, even though they are inorganic
    corecore