The Satellite/Terrestrial Integrated mobile Communication System (STICS), which allows terrestrial mobile phones to communicate directly through a satellite, has been studied [1]. Satellites are unaffected by the seismic activity that causes terrestrial damage, and therefore, the STICS can be expected to be a measure that ensures emergency call connection. This paper first describes the basic characteristics of call blocking rates of terrestrial mobile phone systems in areas where non-functional base stations are geographically clustered, as investigated through computer simulations that showed an increased call blocking rate as the number of non-functional base stations increased. Further simulations showed that restricting the use of the satellite system for emergency calls only ensures the STICS's capacity to transmit emergency communications; however, these simulations also revealed a weakness in the low channel utilization rate of the satellite system [2]. Therefore, in this paper, we propose increasing the channel utilization rate with a priority channel framework that divides the satellite channels between priority channels for emergency calls and non-priority channels that can be available for emergency or general use. Simulations of this priority channel framework showed that it increased the satellite system's channel utilization rate, while continuing to ensure emergency call connection [3]. These simulations showed that the STICS with a priority channel framework can provide efficient channel utilization and still be expected to provide a valuable secondary measure to ensure emergency communications in areas with clustered non-functional base stations during large-scale disasters.

Ultra high definition (UHD) imaging systems have attracted much attention as a next generation television (TV) broadcasting service and video streaming service. However, the state of the art video coding standards including H.265/HEVC has not enough compression rate for streaming, broadcasting and storing UHD. Existing coding standard such as H.265/HEVC normaly use RGB-YCbCr color transform before compressing RGB color image since that procedure can decorrelate color components well. However, there is room for improvement on the coding efficiency for color image based on an observation that the luminance and chrominance components changes in same locations. This observation inspired us to propose a new post-processing method for compressed images by using weighted least square (WLS) filter with coded luminance component as a guide image, for refining the edges of chrominance components. Since the computational cost of WLS tends to superlinearly increase with increasing image size, it is difficult to apply it to UHD images. To overcome this problem, we propose slightly overlapped block partitioning and a new variant of WLS (constrained WLS, CWLS). Experimental results of objective quality comparison and subjective assessment test using 4K images show that our proposed method can outperform the conventional method and reduce the bit amount for chrominance component drastically with preserving the subjective quality.

All-optical 1-to-6 wavelength multicasting of a 10-Gb/s picosecond-tunable-width converted return-to-zero (RZ)-on-off-keying (OOK) data signal using a wideband-parametric pulse source from a distributed Raman amplifier (DRA) is experimentally demonstrated. Width-tunable wavelength multicasting within the C-band with approximately 40.6-nm of separation with various compressed RZ data signal inputs have been proposed and demonstrated. The converted multicast pulse widths can be flexibly controlled down to 2.67 ps by tuning the Raman pump powers of the DRA. Nearly equal pulse widths at all multicast wavelengths are obtained. Furthermore, wide open eye patterns and penalties less than 1.2 dB at the 10-9 bit-error-rate (BER) level are found.

Adherence to coding conventions during the code production stage of software development is essential. Benefits include enabling programmers to quickly understand the context of shared code, communicate with one another in a consistent manner, and easily maintain the source code at low costs. In reality, however, programmers tend to doubt or ignore the degree to which the quality of their code is affected by adherence to these guidelines. This paper addresses research questions such as “Do violations of coding conventions affect the readability of the produced code?”, “What kinds of coding violations reduce code readability?”, and “How much do variable factors such as developer experience, project size, team size, and project maturity influence coding violations?” To respond to these research questions, we explored 210 open-source Java projects with 117 coding conventions from the Sun standard checklist. We believe our findings and the analysis approach used in the paper will encourage programmers and QA managers to develop their own customized and effective coding style guidelines.

In this paper, we propose a method for reconstructing 3D sequential patterns from multiple images without knowing exact image correspondences and without calibrating linear camera sensitivity parameters on intensity. The sequential pattern is defined as a series of colored 3D points. We assume that the series of the points are obtained in multiple images, but the correspondence of individual points is not known among multiple images. For reconstructing sequential patterns, we consider a camera projection model which combines geometric and photometric information of objects. Furthermore, we consider camera projections in the frequency space. By considering the multi-view relationship on the new projection model, we show that the 3D sequential patterns can be reconstructed without knowing exact correspondence of individual image points in the sequential patterns; moreover, the recovered 3D patterns do not suffer from changes in linear camera sensitivity parameters. The efficiency of the proposed method is tested using real images.

This paper presents wireless systems for use in disaster recovery operations. The Great East Japan Earthquake of March 11, 2011 reinforced the importance of communications in, to, and between disaster areas as lifelines. It also revealed that conventional wireless systems used for disaster recovery need to be renovated to cope with technological changes and to provide their services with easier operations. To address this need we have developed new systems, which include a relay wireless system, subscriber wireless systems, business radio systems, and satellite communication systems. They will be chosen and used depending on the situations in disaster areas as well as on the required services.

The global avalanche characteristics measure the overall avalanche properties of Boolean functions, an n-variable balanced Boolean function of the sum-of-square indicator reaching σƒ=22n+2n+3 is an open problem. In this paper, we prove that there does not exist a balanced Boolean function with σƒ=22n+2n+3 for n≥4, if the hamming weight of one decomposition function belongs to the interval Q*. Some upper bounds on the order of propagation criterion of balanced Boolean functions with n (3≤n≤100) variables are given, if the number of vectors of propagation criterion is equal and less than 7·2n-3-1. Two lower bounds on the sum-of-square indicator for balanced Boolean functions with optimal autocorrelation distribution are obtained. Furthermore, the relationship between the sum-of-squares indicator and nonlinearity of balanced Boolean functions is deduced, the new nonlinearity improves the previously known nonlinearity.

Assume that Alice, Bob, and Carol, each of whom privately holds a one-bit input, want to learn the output of some Boolean function, say the majority function, of their inputs without revealing more of their own secret inputs than necessary. In this paper, we show that such a secure three-input function evaluation can be performed with a deck of real cards; specifically, the three players can learn only the output of the function using eight physical cards — four black and four red cards — with identical backs.

To enhance the privacy of vehicle owners, combinatorial certificate management schemes assign each certificate to a large enough group of vehicles so that it will be difficult to link a certificate to any particular vehicle. When an innocent vehicle shares a certificate with a misbehaving vehicle and the certificate on the misbehaving vehicle has been revoked, the certificate on the innocent vehicle also becomes invalid and is said to be covered. When a group of misbehaving vehicles collectively share all the certificates assigned to an innocent vehicle and these certificates are revoked, the innocent vehicle is said to be covered. We point out that the previous analysis of the vehicle cover probability is not correct and then provide a new and exact analysis of the vehicle cover probability.

In this paper, we propose a zero-forcing (ZF) Tomlinson-Harashima precoding (THP) with substream permutations based on the bit rate maximization for single-user MIMO (SU-MIMO) systems. We study the effect of substream permutations on the ZF-THP SU-MIMO systems, when the mean squared error (MSE) and the bit rate are adopted for the selection of the permutation matrix as criteria. Based on our analysis, we propose a method to increase the bit rate by substream permutations, and derive QR and Cholesky decomposition-based algorithms which realize the proposed method. Furthermore, to improve the error rate performance, we apply zero transmission to subchannels with low signal-to-noise ratios. Numerical examples are provided to demonstrate the effectiveness of the proposed THP MIMO system.

The IEEE 802.11 wireless LAN (WLAN) is based on carrier sense multiple access with collision avoidance (CSMA/CA) protocol. CSMA/CA uses a backoff mechanism to avoid collisions among stations (STAs). One disadvantage of backoff mechanisms is that STAs must wait for some period of time before transmission, which degrades spectral efficiency. Moreover, a backoff algorithm cannot completely avoid collisions. We have proposed a novel medium access control (MAC) scheme called the visual recognition-based medium access control (VRMAC) scheme, which uses an LED-camera communication technique. STAs send media-access request messages by blinking their LEDs in VRMAC scheme. An access point (AP) receives the messages via its camera, and then allocates transmission opportunities to the STAs by transmitting control frames. Since the transmission rate of the LED-camera communication is lower than WLAN transmission, the delay of access requesting causes and it could decrease the system throughput of the VRMAC system based WLAN. We reveal the effect of the delay for TCP flows and propose enhanced access procedures to eliminate the effect of the delay. Our simulation results demonstrate that VRMAC scheme increases the system throughput in UDP and TCP traffic. Moreover, the scenario-based evaluations reveal that VRMAC scheme also decreases the session delay which is a metric of quality of experience (QoE) for TCP applications.

The bag-of-words model (BOW) has been extensively adopted by recent human action recognition methods. The pooling operation, which aggregates local descriptor encodings into a single representation, is a key determiner of the performance of the BOW-based methods. However, the spatio-temporal relationship among interest points has rarely been considered in the pooling step, which results in the imprecise representation of human actions. In this paper, we propose a novel pooling strategy named contextual max pooling (CMP) to overcome this limitation. We add a constraint term into the objective function under the framework of max pooling, which forces the weights of interest points to be consistent with their probabilities. In this way, CMP explicitly considers the spatio-temporal contextual relationships among interest points and inherits the positive properties of max pooling. Our method is verified on three challenging datasets (KTH, UCF Sports and UCF Films datasets), and the results demonstrate that our method achieves better results than the state-of-the-art methods in human action recognition.

This manuscript presents a simple scheme to improve the performance of a feedback control system that uses power line channels for its feedback loop. The noise and attenuation of power lines, and thus the signal to noise ratio, are known to be cyclostationary. Such cyclic features in the channel allow us to predict virtually error free transmission instants as well as instants of high probability of errors. This paper introduces and evaluates the effectiveness of a packet transmission scheduling that collaborates with a predictive control scheme adapted to this cyclostationary environment. In other words, we explore the cooperation between the physical and application layers of the system in order to achieve an overall optimization. To rate the control quality of the system we evaluate its stability as well as its ability to follow control commands accurately. We compare a scheme of increased packet rate against our proposed scheme which emulates a high packet rate with the use of predictive control. Through this comparison, we verify the effectiveness of the proposed scheme to improve the control quality of the system, even under low signal to noise ratio conditions in the cyclostationary channel.

Social recommendation systems that make use of the user's social information have recently attracted considerable attention. These recommendation approaches partly solve cold-start and data sparsity problems and significantly improve the performance of recommendation systems. The essence of social recommendation methods is to utilize the user's explicit social connections to improve recommendation results. However, this information is not always available in real-world recommender systems. In this paper, a solution to this problem of explicit social information unavailability is proposed. The existing user-item rating matrix is used to compute implicit social information, and then an ISRec (implicit social recommendation algorithm) which integrates this implicit social information and the user-item rating matrix for social recommendation is introduced. Experimental results show that our method performs much better than state-of-the-art approaches; moreover, complexity analysis indicates that our approach can be applied to very large datasets because it scales linearly with respect to the number of observations in the matrices.

To represent interactive objects, we propose a choice-disjunctive declaration statement of the form $S add R$ where S, R are the (procedure or field) declaration statements within a class. This statement has the following semantics: request the user to choose one between S and R when an object of this class is created. This statement is useful for representing interactive objects that require interaction with the user.

In the scattering problem of dielectric gratings in conical mounting, we have considered and formulated scattering fields using transverse electric (TE) and transverse magnetic (TM) waves. This paper formulates scattering fields by superpositions of right-circularly (RC) and left-circularly (LC) polarized waves through the matrix eigenvalue method.

We deposited thin films of thiophene/phenylene co-oligomers (TPCOs) onto poly(tetrafluoroethylene) (PTFE) layers that were friction-transferred on substrates. These films were composed of aligned molecules in such a way that their polarizations of emissions and absorbances were larger along the drawing direction than those perpendicular to that direction. Organic field-effect transistors (OFETs) fabricated with these films indicated large mobilities, when the drawing direction of PTFE was parallel to the channel length direction. The friction-transfer technique forms the TPCO films that indicate the anisotropic optical and electronic properties.

The success of heuristic search in AI planning largely depends on the design of the heuristic. On the other hand, previous experience contains potential domain information that can assist the planning process. In this context, we have studied dynamic macro-based heuristic planning through action relationship analysis. We present an approach for analyzing the action relationship and design an algorithm that learns macros in solved cases. We then propose a dynamic macro-based heuristic that appropriately reuses the macros rather than immediately assigning them to domains. The above ideas are incorporated into a working planning system called Dynamic Macro-based Fast Forward planner. Finally, we evaluate our method in a series of experiments. Our method effectively optimizes planning since it reduces the result length by an average of 10% relative to the FF, in a time-economic manner. The efficiency is especially improved when invoking an action consumes time.

Video traffic occupies a major part of current mobile traffic. The characteristics of video traffic are dominated by the behavior of the video application users. This paper uses a state transition diagram to analyze the behavior of video application users on smart phones. Video application users are divided into two categories; keyword search users and initial screen users. They take different first action in video viewing. The result of our analysis shows that the patience of video application users depends on whether they have a specific purpose when they launch a video application or not. Mobile network operators can improve the QoE of video application users by utilizing the results of this study.

In recent years, there has been growing interest in systems for sharing resources, which were originally used for personal purposes by individual users, among many unspecified users via a network. An example of such systems is a peer-to-peer (P2P) data storage system that enables users to share a portion of unused space in their own storage devices among themselves. In a recent paper on a P2P data storage system, the user behavior model was defined based on supply and demand functions that depend only on the storage space unit price in a virtual marketplace. However, it was implicitly assumed that other factors, such as unused space of storage devices possessed by users and additional storage space asked by users, did not affect the characteristics of the supply and demand functions. In addition, it was not clear how the values of parameters used in the user behavior model were determined. Therefore, in this paper, we modify the supply and demand functions and determine the values of their parameters by taking the above mentioned factors as well as the price structure of storage devices in a real marketplace into account. Moreover, we provide a numerical example to evaluate the social welfare realized by the P2P data storage system as a typical application of the modified supply and demand functions.