Abstract Broadcast Encryption (BE) is public-key encryption allowing a sender to encrypt a message by specifing recipients, and only the specified recipients can decrypt the message. In several BE applications, since the privacy of recipients allowed to access the message is often as important as the confidentiality of the message, anonymity is introduced as an additional but important security requirement for BE. Kiayias and Samari (IH 2013) presented an asymptotic lower bound on the ciphertext sizes in BE schemes satisfying anonymity (ANO-BE for short). More precisely, their lower bound is derived under the assumption that ANO-BE schemes have a special property. However, it is insufficient to show their lower bound is asymptotically tight since it is unclear whether existing ANO-BE schemes meet the special property. In this work, we derive asymptotically tight lower bounds on the ciphertext size in ANO-BE by assuming only properties that most existing ANO-BE schemes satisfy. With a similar technique, we first derive asymptoticallyPlease provide MSC codes. For more details, please visit http://www.ams.org/msc/. tight lower bounds on the authenticator sizes in Anonymous Broadcast Authentication (ABA). Furthermore, we extend the above result and present (non-asymptotically) tight lower and upper bounds on thePlease check and confirm the Running title. ciphertext sizes in ANO-BE. We show that a variant of ANO-BE scheme proposed by Li and Gong (ACNS 2018) is optimal. We also provide tight bounds on the authenticator sizes in ABA via the same approach as ANO-BE, and propose an optimal construction for ABA.

The FMCW radar has lots of advantages such as compact, energy effective and low cost. It is suitable for mounting on the vehicle and also on small sized UAV. In this paper, the high squint angle effect is considered for both the FMCW synthetic aperture radar (SAR) and the inverse synthetic aperture radar (ISAR) in the case of the high resolution vehicle radar. The 2ndrange compression is performed for removing the range and the azimuth coupling effect under the high squint angle situation. The polar reformatting is performed for improving the radar resolution in the ISAR. By keeping practical situation in mind, the image qualities under the squint angle with random error is investigated. In addition, the simulation software for the SAR and the ISAR are developed.

Synthetic aperture radar automatic target recognition (SAR-ATR) typically consists of 3 main stages: preprocessing(also known as prescreening), feature extraction, and classification. For high-dimensional feature space, the computation time required to construct it by sequential programming is considerably long. In this study, parts of an ATR system, in particular the feature extraction stage, were implemented on Graphics Processing Unit (GPU) for speed up. For Moving and Stationary Target Acquisition and Recognition (MSTAR) data set, the 3-stage ATR process constructing a 28-dimension feature space using 2987 samples performed over 6 times faster running a GPU implemented code than that of a sequential code on average.

This paper deals with ship scheduling and inventory management by considering both shipping costs and demurrage costs with hourly precision. First, the formulation of an optimization model of the problem is described. Then, a hierarchical scheduling approach is newly introduced, which enables us to get a schedule close to the optimal within reasonable computational time. Moreover, through some computational experiments with some examples of practical size, the effectiveness of the proposed approach is examined, where the results obtained by using the proposed approach are compared with those by directly optimization method based on the mathematical programming approach and by heuristic method based on the rule-based approach. Finally, the effectiveness and the potential of the proposed approach with respect to the balance between the quality of the obtained schedule and the time required for computation are confirmed.

In this paper, a general scheme for complete model-based decomposition of the polarimetric synthetic aperture radar (POLSAR) coherency matrix data is presented. We show that the POLSAR coherency matrix can be completely decomposed into three components contributed by volume scattering and two single scatterers (characterized by rank-1 matrices). Under this scheme, solving for the volume scattering power amounts to a generalized eigendecomposition problem, and the nonnegative power constraint uniquely determines the minimum eigenvalue as the volume scattering power. Furthermore, in order to discriminate the remaining components, we propose two approaches. One is based on eigendecomposition, and the other is based on model fitting, both of which are shown to properly resolve the surface and double-bounce scattering ambiguity. As a result, this paper in particular contributes to two pending needs for model-based POLSAR decomposition. First, it overcomes negative power problems, i.e., all the decomposed powers are strictly guaranteed to be nonnegative; and second, the three-component decomposition exactly accounts for every element of the observed coherency matrix, leading to a complete utilization of the fully polarimetric information.

In this letter, an advanced version of the hybrid Freeman/eigenvalue decomposition technique for land parameter extraction is presented with an illustrative example of application. The motivation arises from decomposition problems in obtaining a meaningful volume scattering estimation, so that the technique can be used for both oriented objects and vegetation/forest areas. The idea is to improve the accuracy of the required parameter extraction. Two strategies are adopted to increase the applicability of a hybrid Freeman/eigenvalue decomposition technique: One is the unitary transformation of the coherency matrix; the other is to use an extended volume scattering model. The extension of the volume scattering model plays an essential role for the hybrid Freeman/eigenvalue decomposition technique. Since the volume scattering power is evaluated by assuming that the$HV$component is caused by vegetation only in the existing technique, an extended volume scattering power approach is utilized. It is shown that vegetation areas and oriented objects such as urban building areas are well discriminated by the proposed technique as compared to the existing techniques.

The statistical behavior of the sea clutter in synthetic aperture radar (SAR) images is characterized by both the marginal distribution and the spatial correlation. However, simultaneous modeling of the joint information remains a difficult job because of the non-Gaussian clutter nature. In this paper, a semiparametric approach is proposed for addressing this problem. First, we investigate the applicability of the nonparametric kernel density estimator (KDE) for estimating the marginal distribution of the SAR clutter and show that the KDE is most applicable in the log-intensity domain. Second, we propose to estimate the underlying spatial correlation structure with a copula approach and show that the Gaussian copula is a sufficiently accurate model. Consequently, the KDE, together with the Gaussian copula, offers a full characterization of the joint probability distribution, based on which a quadratic detector of null distribution governed by the well-known chi-squared law can be conveniently designed for constant false alarm rate detection. In the experiment, results with both simulated and real SAR data demonstrate that, compared with the single-point detector using only the marginal distribution, the proposed method, which incorporates spatial correlation, significantly improves the detection performance with regard to either the receiver-operating-characteristic curve or detected target pixels. The tradeoff, however, lies in a loss of false alarm rate control resulting from increased uncertainty in estimating higher dimensional distributions.

This paper introduces a novel method for filtering polarimetric synthetic aperture radar (POLSAR) imagery data. Unlike most existing filters, the proposed one is freed from using searching windows but implements the filtering in a sequential fashion. Specifically, we propose to use the inverse Wishart distribution as the conjugate prior model for the coherency matrix (CM) data and show that the maximum a posteriori (MAP) solution leads to a very simple linear recursive formula for estimate update, through which issues such as feature preservation and bias correction can be also taken into account. In the experiment, the proposed method is tested on the POLSAR dataset acquired by the DLR (Germany Aerospace Center) F-SAR system. Results demonstrate that the filter shows inspiring performances in terms of both noise reduction and feature preservation.

In this study, changes of the L-band PALSAR polarimetric signal scattered from earthquake/tsunami damaged areas has been investigated. Since it is not always possible to get data sets having sufficiently good spatial/temporal resolutions to detect large area of damages precisely, it is of specific interest to use of wave polarization information appropriate to assess disaster-induced changes of scattering phenomena. Experimental results indicate that different polarimetric parameters and similarity measures provide complimentary information on damages. Consequently, it is important to utilize polarimetric features maximizing target changes and minimizing the false-alarm and the missed-alarm rates in developing damage assessment algorithms.

Battery performance of a smartphone is high priority for smartphone users. Wireless networking such as WEB browsing, SNS, contents download consumes one third of energy consumption of smartphone use case. As 3G-4G interface spends much power, it may recommend that using WLAN is more efficient for battery life. The various power-saving methods for WLAN have been discussed, but such solutions need modification of network infrastructure. Therefore, it is difficult to adequate current system. In this paper, we present a cross-layer power save method which can coexist with related works. The proposed method controls TCP-acknowledgement transmission depends on wireless channel quality and network quality. This method does not need any modification to current infrastructure, and can save battery power without Network performance degradation.

Personal area networks (PANs) are networks in which portable devices carried by a user are connected to each other by wireless interfaces. Mobile personal area networks (MPANs) allow a PAN to be mobile, enabling seamless Internet access even when the user is moving. A PAN router has a wireless access interface and connects the devices in the MPAN to the Internet. There might be two or more MPAN routers in an MPAN and it is necessary for the MPAN router most suitable for the location and/or situation to be in operation. For example, if the MPAN router currently operating as the default router fails, another available MPAN router should start to operate as the default, or an MPAN router might be selected from those available according to QoS. We propose methods for the switching and selection of MPAN routers. We show by experiment that they enable fast switching and selection of the MPAN router most suitable for various QoS.

Radiances observed by the Interferometric Monitor for Greenhouse gases sounder have been used to retrieve temperature, water vapor, and ozone profiles. It is shown that the sounder allows one to simultaneously retrieve stable solutions for temperature and water vapor. Once water vapor and temperature have been retrieved, ozone profile may be estimated on the same fine vertical mesh as water vapor and temperature. Comparison among calculated and observed radiances shows good agreement in several parts of the thermal band which is sensed by the sounder. A slight discrepancy is observed in the wing region of the 720-cm/sup -1/ CO/sub 2/ Q-branch, whereas the most severe form of disagreement is seen in the 6.7-/spl mu/m vibrational H/sub 2/O absorption band. Nevertheless, suitable spectral ranges may be identified which yield accurate and stable inversions for temperature, water vapor, and ozone.

The interferometric monitor for greenhouse gases (IMG) was the precursor of the high-resolution FTIR aboard on the satellite for Earth observation. The IMG sensor was aboard the advance Earth observing satellite (ADEOS) launched on August 17, 1996. The IMG operated for only eight months; however, the high-resolution thermal infrared spectra obtained provided abundant information on global atmospheric phenomena and the first global maps of greenhouse gases retrieved from the spectra. This paper describes the operation experience in orbit and the evaluation results for the hardware and the products obtained from the IMG observations.