Although web-based remote collaboration systems are getting popular, they are not suitable for long-distance or demanding use cases due to the web browser limitations. To cover wider range of use cases, we propose novel architecture for web-based remote collaboration systems. The main features are relay-servers, overlay-managers, and timecode-servers. The relay-servers enable the web-based systems to exchange data smoothly and locally even in long-distance collaboration. The overlay-managers and timecode-servers enable web-based systems to deal with native applications in order to provide high quality collaboration experience. A prototype is implemented and tested to confirm that the proposal can construct unprecedented collaboration systems suitable for long-distance and demanding collaboration scenarios; targets not possible with conventional web-based collaboration systems.

To ensure the reliability of distributed storage systems, we studied network bandwidth-aware multiple fault tolerant erasure codes. A flat XOR code is one of the sparse graph codes designed for distributed storage systems. It encodes and decodes data by exclusive OR (XOR) operation with low complexity. However, conventional construction methods of flat XOR codes are not optimal in terms of repair bandwidth. In this paper, we propose two novel constructions of irregular flat XOR code that can remarkably reduce repair bandwidth compared to conventional flat XOR codes and Reed-Solomon codes. Our irregular flat XOR codes also reduce repair bandwidth compared to flat XOR codes designed by the Monte-Carlo method.

Recently, over 100 Gbit/s ultra-high-speed shared IP networks have become available. The large bandwidth they provide can be shared among various users to transmit not only data but also high-quality video through a virtualized network (VN) configured with software defined network (SDN) technology on the shared IP network. The VN can also be reconfigured in case there is not enough bandwidth for the video transmission. However, in this case, video transmission will be interrupted because slice reconfiguration requires a certain amount of time to configure all the switches again. To address this problem, a "Dynamic SDN" method is proposed that makes use of Network Address Translation (NAT) based overlay SDN technology. The method creates a VN from virtual paths hop-by-hop, instead of a slice based VN, by using OpenFlow (OF) switches, an OF controller, high-accuracy traffic monitors, and a controller node (NAT manager). In an experiment, it was used to construct a VN and a video on-demand system on existing research and education networks between Japan and the US. During the experiment, 1.6 Gbit/s uncompressed HD video was transferred in real time through the VN. The experiment results confirmed the method enabled uncompressed HD video to be transferred through the VN and also enabled a virtual path to be switched dynamically without interruption.

The main contribution of this paper is to develop a method for alleviating fatigue during handling medium-weight objects and augmenting our endurance by affecting our weight perception with augmented reality technology. To assist people to lift medium-weight objects without a complex structure or various costs, we focus on the phenomenon that our weight perception during handling objects is affected by visual properties. Our hypothesis is that this illusionary effect in weight perception can be applied to reduce fatigue while handling medium-weight objects without mechatronics-based physical assistance. In this paper, we propose an augmented reality system that changes the brightness value of an object in order to reduce fatigue while handling the object. We conducted two fundamental experiments to investigate the effectiveness of the proposed system. Our results suggested that the system eliminates the need to use excess energy for handling objects and reduces fatigue during the handling task.

Hierarchical unstructured peer-to-peer (P2P) networks for file sharing systems such as Gnutella and Kazaa have made a tremendous achievement in the last decade. However, while these P2P networks can be tolerant to churn, i.e., the dynamics of peer participation and departure (or fault), there still remains the issue of vulnerability to Denial of Service (DoS) attacks, i.e., when the highest degree peers are removed. In order to overcome this shortcoming, we focus on a bimodal degree distribution, which is tolerant to both churn and DoS attacks. However, the network topology affects the network stability that was not taken into considered in the previous works. Therefore, we analyze the optimal network topology for DoS attack tolerance, and accordingly develop the peer joining procedure to construct and maintain the proposed network topology. Our proposed scheme is dubbed THUP (churn/DoS Tolerant, Hierarchical, Unstructured, P2P network). Performance evaluation conducted through computer simulations shows that THUP substantially improves the stability and communication efficiency compared with other existing P2P networking structures.

Digital cinema is a promising application that utilizes high-speed optical networks to transfer super-high-definition (SHD) images. The networks are primarily used for distributing digital cinema contents in packet data form, and are also used to support new services such as the live streaming of musicals and sport games to movie theaters. While current transfer services offer high-definition (HD) quality video, live-streaming applications will soon shift to providing cinema quality 4K content to both business and movie theaters users. The extra-high-quality 4K format enables a realistic telepresence, and will be combined with special tools such as video editing systems to realize effective remote collaboration for business workspaces. This paper introduces successive research on SHD image transmission and its application, especially in digital cinema and associated application fields.

In this paper we propose a method of constructing packet-level LDGM codes that offer backward compatibility with conventional viewing devices. Our proposed method makes it possible to watch content even if the viewer does not support any FEC module. Moreover, the method also improves the coding efficiency through the combined use of packet division and interleaving methods. In general, there is a tradeoff between computation complexity and performance, but our proposed method improves coding efficiency by using a message passing decoding scheme that does not require any additional computation. The coding efficiency of the proposed method is evaluated both experimentally and theoretically.

A new bit allocation scheme for JPEG 2000 systems in parallel-distributed environments is proposed. In recent years, super high-definition images are being used for not only digital cinema also alternative services e.g. real-time sports in theaters. In general, such high-definition images are divided into small segments, such as tiles or components, and compressed. However, this process leads to low coding efficiency. In contrast, our proposed scheme controls the bit allocation ratio for each color-component separately by using the quantizer properties available in the JPEG 2000 standard. Simulation results show that the proposed scheme achieves the same coding performance as the non parallel-distributed approach.

Distributed video coding (DVC) is attracting attention as a paradigm for video compression. One reason is that it transfers the high complexity computation to the decoder. However, the DVC decoder that uses channel coding based on a belief propagation algorithm has complexity exceeding that of the H.264/AVC encoder. This paper proposes a parallelized DVC scheme that treats each bitplane independently. Unfortunately, simple parallelization schemes suffer low compression efficiency because they can't use additional side information for the decoding of subsequent bitplanes. Therefore, we propose an effective estimation method that can calculate the bit probability as accurately as possible by index assignment. Simulations show that the proposed system can reduce the decode time by up to about 30-35 [%] with only slight parallelization loss.

We introduce a prototype digital cinema system that can store, transmit, and display extra high quality movies with the scanning resolution of 2048 lines. The system was designed to distribute cinema contents on optical IP networks offering Gigabit Ethernet. The system combines a video server, a decoder, and a projector to show movies of 3840 /spl times/ 2048 pixels with 24 bit color depth at 24 frames per second. Films are digitized and compressed by motion JPEG. The streams, which average 250 Mbps, are continuously transmitted from the PC-based server to the real-time decoder using TCP/IP. The real-time decoder is a cluster of parallel JPEG processors to decode the received streams into uncompressed movie data (4.5 Gbps). The projector uses three LCD panels, each offering 8 million-pixels, and an all-digital video interface in order to enhance the quality of the digital cinema.

This paper proposes a unified coding algorithm for lossless and near-lossless compression of still color images. The algorithm can control the Peak Signal-to-Noise Ratio (PSNR) of the reconstructed image. Furthermore, the distortion on the RGB plane is suppressed to within the level of /spl plusmn/p, where p is a certain small non-negative integer. In order to control the PSNR of the reconstructed image, an adaptive quantizer is designed on the basis of human visual criteria. Experimental results confirm the effectiveness of the proposed algorithm.

This paper proposes a unified coding algorithm for lossless and near-lossless color image compression that exploits the correlations between RGB signals. For lossless coding, a reversible color transform is proposed that removes the correlations between RGB signals while avoiding any finite word length limitation. Next, the lossless algorithm is extended to a unified coding algorithm of lossless and near-lossless compression that can control the distortion level in the magnitude on the RGB plane. Experimental results show the effectiveness of the proposed algorithm.

A technique is described for real-time solder joint inspection for printed wiring boards. It uses reflection on the specular solder surface projected by a straight-shaped light source (a straight fluorescent tube). For image processing, modified Hough transformation is adopted to approximate the image of the fluorescent tube reflected on a solder joint to a straight line. These processes are performed on special-purpose hardware to achieve video-rate processing. Experimental results have demonstrated sufficient detection capability.>