175 research outputs found

    A DEVELOPMENT OF A MUA TO MAKE PICTOGRAPH MAIL FOR CHILDREN

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    In recent years, children have begun using computers actively. With this situation, they are beginning to learn how to operate a mail user agent (Hereafter, called MUA) to adaptation to an information society. However, the user interface of general MUAs is not designed with them in mind. Specifically, many unnecessary menu items exist on the user interface of general MUAs. Moreover, the menu text contains many difficult characters (called Kanji) in Japan. In this situation, it is difficult to say that children could learn how to operate the MUA without being confused by the complex user interface. We consider it to be important that even children who have not learned Kanji can use the user interface. To solve this issue, we have developed a MUA that has a simple user interface only represented in Hiragana. In order to create a simple user interface for child use, it is necessary to reduce the number of menu items. Along with this, the number of available functions on this MUA has decreased. However, we think it is rather important to prevent the confusion and unexpected behavior of children. It is also necessary to devise a function to make an e-mail to attract the interest of them. Therefore, we have implemented a function to generate pictograph mail easily.We are using the XML-based User Interface Language (Hereafter, called XUL) to build a user interface for children. It is a language used to build the user interface of Mozilla applications like Firefox and Thunderbird. By using it, we can customize the user interface of Thunderbird to fit any purpose. By these improvements, we think children will be able to use the MUA actively and with enjoyment without falling into confusion

    Quantum Collision Attacks on Reduced SHA-256 and SHA-512

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    In this paper, we study dedicated quantum collision attacks on SHA-256 and SHA-512 for the first time. The attacks reach 38 and 39 steps, respectively, which significantly improve the classical attacks for 31 and 27 steps. Both attacks adopt the framework of the previous work that converts many semi-free-start collisions into a 2-block collision, and are faster than the generic attack in the cost metric of time-space tradeoff. We observe that the number of required semi-free-start collisions can be reduced in the quantum setting, which allows us to convert the previous classical 38 and 39 step semi-free-start collisions into a collision. The idea behind our attacks is simple and will also be applicable to other cryptographic hash functions

    Cryptanalysis against Symmetric-Key Schemes with Online Classical Queries and Offline Quantum Computations

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    In this paper, quantum attacks against symmetric-key schemes are presented in which adversaries only make classical queries but use quantum computers for offline computations. Our attacks are not as efficient as polynomial-time attacks making quantum superposition queries, while our attacks use the realistic model and overwhelmingly improve the classical attacks. Our attacks convert a type of classical meet-in-the-middle attacks into quantum ones. The attack cost depends on the number of available qubits and the way to realize the quantum hardware. The tradeoff between data complexity DD and time complexity TT against the problem of cardinality NN is D2T2=ND^2 \cdot T^2 =N and DT6=N3D \cdot T^6 = N^3 in the best and worst case scenarios to the adversary respectively, while the classic attack requires DT=ND\cdot T = N. This improvement is meaningful from an engineering aspect because several existing schemes claim beyond-birthday-bound security for TT by limiting the maximum DD to be below 2n/22^{n/2} according to the classical tradeoff DT=ND\cdot T = N. Those schemes are broken if quantum offline computations are performed by adversaries. The attack can be applied to many schemes such as a tweakable block-cipher construction TDR, a dedicated MAC scheme Chaskey, an on-line authenticated encryption scheme McOE-X, a hash function based MAC H2^2-MAC and a permutation based MAC keyed-sponge. The idea is then applied to the FX-construction to discover new tradeoffs in the classical query model

    Relationship between surface roughness and turbulence of natural winds near the ground surface

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    The design of low-rise buildings such that they can handle wind loads makes it necessary to accurately evaluate those wind loads, both on the structural framework and on the cladding/components. To this end, it is necessary to fully understand the characteristics of the wind near the ground around a building. This study sets out to develop a quantitative means of estimating the turbulence of the wind near the surface of the ground, based on field measurements obtained at different points across Japan. The surface roughness is evaluated based on several factors taken from a building information database. The relationship between these factors and the turbulence of the wind is discussed. The effect of the observation height, relative to the surface of the ground, on the turbulence is also investigated

    Effect of selected splenic irradiation on growth of meth A-fibrosarcoma in mice and partial characterization of splenic effector and suppressor cell populations.

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    Meth A-fibrosarcoma bearing BALB/c mice were subjected to selected splenic irradiation (2.0-4.0 Gy) on days 7 and 14 of tumor growth. Tumor growth was recorded by serial measurement. Irradiation given on day 7 caused regression of tumor, but irradiation given on day 14 did not show tumor regression. Antitumor activity in the Winn assay was detected in spleen cells 3 days after irradiation, but was not detected 7 days after. The cell surface phenotypes were analyzed on days 3, 7 and 14 of splenic irradiation using monoclonal antibodies (anti-Thy1.2 antibody, anti-Lyt1 antibody, anti-Lyt2 antibody, anti-L3T4 antibody) by flow cytometry. Thy 1.2, Lyt1, and L3T4 cells were increased on day 3 of splenic irradiation, but were not on days 7 and 14. Lyt2-cells did not show increase on days 3, 7 and 14. It was possibly suggested that selected splenic irradiation induced tumor regression was caused by the ability of irradiation to preferentially eliminate suppressor T cells, thereby allowing effector T-cells to become relatively dominant.</p

    Downregulation of CD4 is required for maintenance of viral infectivity of HIV-1

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    AbstractDownregulation of virus receptors on the cell surface is considered to be important in preventing superinfection. HIV-1 encodes multiple gene products, Env, Vpu, and Nef, involved in downregulation of CD4, a major HIV-1 receptor. We found that simultaneous mutations in both vpu and nef severely impaired virus replication. We examined the involvement of CD4 downregulation mediated by Vpu and Nef in the modification of virus infectivity. The mutation in vpu increased CD4 incorporation into virions without affecting the Env content in it, inhibiting the attachment step of virions to the CD4-positive cell surface. Although a single mutation in nef suppresses virus infectivity via a CD4-independent mechanism, it could augment CD4 incorporation in virions in combination with a vpu mutation. These results indicated that CD4 downregulation was necessary for maintenance of Env function in the virion

    Articulated Trajectory Mapping for Reviewing Walking Tours

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    This paper addresses how to enrich a map-based representation for reviewing walking tours with the features of trajectory mapping and tracing animation. Generally, a trajectory generated by raw GPS data can often be difficult to browse through on a map. To resolve this issue, we first illustrated tangled trajectory lines, inaccurate indoor positioning, and unstable trajectory lines as problems encountered when mapping raw trajectory data. Then, we proposed a new framework that focuses on GPS horizontal accuracy to locate indoor location points and find stopping points on an accelerometer. We also applied a conventional line simplification algorithm to make the trajectory cleaner and then integrated the extracted points with the clean trajectory line. Furthermore, our experiments with some actual logs of walking tours demonstrated that articulated trajectory mapping, which comprises simplification and characterization methods, sufficiently reliable and effective for better reviewing experiences. The paper contributes to the research on cleaning up map-based displays and tracing animations of raw trajectory GPS data by using not only location data but also sensor data that smartphones can collect

    Intensity-modulated irradiation for superficial tumors by overlapping irradiation fields using intensity modulators in accelerator-based BNCT

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    The distribution of the thermal neutron flux has a significant impact on the treatment efficacy. We developed an irradiation method of overlapping irradiation fields using intensity modulators for the treatment of superficial tumors with the aim of expanding the indications for accelerator-based boron neutron capture therapy (BNCT). The shape of the intensity modulator was determined and Monte Carlo simulations were carried out to determine the uniformity of the resulting thermal neutron flux distribution. The intensity modulators were then fabricated and irradiation tests were conducted, which resulted in the formation of a uniform thermal neutron flux distribution. Finally, an evaluation of the tumor dose distribution showed that when two irradiation fields overlapped, the minimum tumor dose was 27.4 Gy-eq, which was higher than the tumor control dose of 20 Gy-eq. Furthermore, it was found that the uniformity of the treatment was improved 47% as compared to the treatment that uses a single irradiation field. This clearly demonstrates the effectiveness of this technique and the possibility of expanding the indications to superficially located tumors

    Development of optimization method for uniform dose distribution on superficial tumor in an accelerator-based boron neutron capture therapy system

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    To treat superficial tumors using accelerator-based boron neutron capture therapy (ABBNCT), a technique was investigated, based on which, a single-neutron modulator was placed inside a collimator and was irradiated with thermal neutrons. In large tumors, the dose was reduced at their edges. The objective was to generate a uniform and therapeutic intensity dose distribution. In this study, we developed a method for optimizing the shape of the intensity modulator and irradiation time ratio to generate a uniform dose distribution to treat superficial tumors of various shapes. A computational tool was developed, which performed Monte Carlo simulations using 424 different source combinations. We determined the shape of the intensity modulator with the highest minimum tumor dose. The homogeneity index (HI), which evaluates uniformity, was also derived. To evaluate the efficacy of this method, the dose distribution of a tumor with a diameter of 100 mm and thickness of 10 mm was evaluated. Furthermore, irradiation experiments were conducted using an ABBNCT system. The thermal neutron flux distribution outcomes that have considerable impacts on the tumor’s dose confirmed a good agreement between experiments and calculations. Moreover, the minimum tumor dose and HI improved by 20 and 36%, respectively, compared with the irradiation case wherein a single-neutron modulator was used. The proposed method improves the minimum tumor volume and uniformity. The results demonstrate the method’s efficacy in ABBNCT for the treatment of superficial tumors

    Direct Supply Chain from Forest to House Builder: A Japanese Business Model

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    AbstractWe developed a direct supply chain from a forest to a house builder for environment-friendly wooden long-life housing based on the “progressive market-in” method. This business model successfully incorporates the external environmental value of the house into its market price.In this paper, we discuss the direct supply chain business model and its environmental effect in Japan, using a micro approach (for individual economic bodies) and a macro approach for the country
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