The demand for large-capacity, latency sensitive applications such as ultra-high-definition video transmission is increasing in wireless communication systems. In the next-generation wireless local area network (LAN), multi-access point (AP) coordination technique is attracting attention for the purpose of reducing collision probability and improving throughput. In high-demand applications such as ultra-high-definition video transmission, there is a problem that increasing the capacity of wireless communication does not necessarily lead directly to their successful implementation. To accommodate more applications, it is important to enhance video throughput calculated based on whether the requirements for ultra-high-definition video transmission are satisfied. Considering the requirements of video transmission, when multi-APs coordinate and allocate each station (STA) to a radio resource, the number of patterns of when and to which STAs resources should be allocated becomes enormous. As a result, it is difficult to find an optimal resource allocation. Therefore, we propose a radio resource allocation for video transmission, utilizing reinforcement learning (RL). We consider two kinds of RL, which are single agent reinforcement learning (SARL) and multi-agent reinforcement learning (MARL). Our computer simulations demonstrate that MARL can achieve performance comparable to that of SARL while requiring minimal information exchange.

To receive effective treatment during emergency response due to seizures or unforeseen accidents, a patient with intractable diseases must disclose information about their disease to an emergency physician. If the patient loses consciousness while traveling, the patient should disclose this information to a companion in advance. However, disclosing this information to a companion is undesirable because the information is confidential. Thus, we propose a system that discloses specific information on intractable diseases only when an emergency physician has verified they possess a medical license. Otherwise, the proposed system only discloses appropriate first aid information. We implemented a prototype of the proposed under the assumption that a physician has a digital medical license based on verifiable credentials (i.e., a standard for digital credentials). With this system, the patient does not disclose confidential information to the patient’s companion but does disclose necessary information to the emergency physician.

The demand for large-capacity, latency sensitive applications such as ultra-high-definition video transmission is increasing in wireless communication systems. In the next-generation wireless local area network (LAN), multi-access point (AP) coordination technique is attracting attention for the purpose of reducing collision probability and improving throughput. In high-demand applications such as ultra-high-definition video transmission, there is a problem that increasing the capacity of wireless communication does not necessarily lead directly to the realization of such applications. Therefore, to improve the number of applications that can be realized, the authors have studied application proportional fairness (APF), which is a radio resource control technique that improves the video throughput calculated based on whether the requirements for ultra-high-definition video transmission are satisfied. Since APF considers only application requirements and does not consider wireless quality, it cannot support multi-AP coordination. In this paper, we modify APF to take radio quality into account to support multi-AP coordination and demonstrate its effectiveness through computer simulations.

Improvements in fabrication devices such as 3D printers are becoming possible for personal fabrication to freely fabricate any products. To clarify who is liable for the product, the fabricator should keep the fabrication history in an immutable and sustainably accessible manner. In this paper, we propose a new scheme, "Fabchain," that can record the fabrication history in such a manner. By utilizing a scheme that employs a blockchain as an auditable communication channel, Fabchain manages print jobs for the fabricator’s 3D printer over the blockchain, while maintaining a history of a print job. We implemented Fabchain on Ethereum and evaluated the performance for recording a print job. Our results demonstrate that Fabchain can complete communication of a print job sequence in less than 1 minute on the Ethereum test network. We conclude that Fabchain can manage a print job in a reasonable duration for 3D printing, while satisfying the requirements for immutability and sustainability.

In recent years, Internet Data Center (IDC) network operation with IPv6 single-stack gathers attention because of IPv4 address pool exhaustion and the high operational load associated with IPv4/IPv6 dual-stack. Since IPv4 traffic still accounts for a large percentage of the total Internet traffic, it is necessary to provide IPv4 services even in IPv6 single-stack networks. A method of providing IPv4 accessibility in an IPv6 single-stack network is known as IPv4 as a Service (IPv4aaS); there are three possible approaches. This research proves that IPv4/IPv6 translation is the most compatible and effective for IDC network operations. The SIIT-DC network design has been standardized as a way to provide IPv4 services with IPv4 / IPv6 Translation. In SIIT-DC, a translation node referred to as Border Relay (BR) is connected between the IPv4 Internet and an IPv6 IDC network in order to translate IPv4 and IPv6 mutually (in order to enable IPv4 service provision in IPv6 server). However, to operate an SIIT-DC network without the lack of redundancy and operational load spikes in multi-homing networks, the Explicit Address Mapping Table (EAMT) must be shared dynamically and consistently with BRs. This paper compares approaches to control EAMT dynamically in SIIT-DC environment and clarifies the benefits and drawbacks of each. The results are expected to contribute to the design of IPv6 single-stack networks in IDC.

In this paper, we propose a novel soft interference cancellation scheme considering processing delay for uplink ultra-reliable and low latency communication (URLLC). For URLLC, repetition transmission was specified to satisfy a requirement of reliability. In a conventional scheme, the performance is improved by combining bit log-likelihood ratios (LLRs) at each repetition transmission. Although it is ordinal to secure radio resources for single URLLC user equipment (UE) to avoid severe inter-UE interference (IUI), it is effective to share a radio resource among plural UEs to increase spectrum efficiency. By introducing the soft interference cancelation, the proposed scheme can efficiently suppress the negative impact of IUI while keeping the similar processing delay as the conventional scheme.

We propose a novel technique that aggregates multiple sensor streams generated by totally different types of sensors into a visually enhanced video stream. This paper shows major features of SENSeTREAM and demonstrates enhancement of user experience in an online live music event. Since SENSeTREAM is a video stream with sensor values encoded in a two-dimensional graphical code, it can transmit multiple sensor data streams while maintaining their synchronization. A SENSeTREAM can be transmitted via existing live streaming services, and can be saved into existing video archive services. We have implemented a prototype SENSeTREAM generator and deployed it to an online live music event. Through the pilot study, we confirmed that SENSeTREAM works with popular streaming services, and provide a new media experience for live performances. We also indicate future direction for establishing visual stream aggregation and its applications.

This paper proposes a frequency-domain (FD) scheduling for an uplink single carrier non-orthogonal multiple access (SC-NOMA) with the assistance of iterative interference cancellation (IC). In the SC-NOMA, an evolved Node B (eNB) with an iterative IC receiver is capable of allocating overlapped spectra to plural intra-cell user equipments (UEs) exceeding the number of receive antennas. As a result, the SC-NOMA can enhance the spectral efficiency owing to the non-orthogonal multiplexing. However, when the subband (SB) criterion scheduling, that assigns an SB to a UE on the basis of the metric only on an SB, is applied, this scheduling is not suitable in the SC-NOMA. This is because the throughput in single carrier transmission depends on all the allocated SBs. Therefore, we propose a novel FD scheduling based on the expected value of cell throughput which is calculated by both the SB selected by the metric as a candidate and the previously allocated SBs. The eNB assigns the candidate SB if the expected cell throughput increases after allocating the candidate SB. Computer simulations confirm that the proposal can improve throughput performances compared to the SB criterion scheduling in the SC-NOMA.

The usage of the mobile phone becomes more diversified, as smart phone users increase and data transmission speed becomes faster by LTE. It is difficult to monitor the network service and maintain stable service quality with the NE-focused monitoring OSS (Operation Support System). In this paper, we show the concept and required functions of the service quality monitoring for mobile networks. Additionally, we propose the implementation of the service quality monitoring OSS to achieve the efficient O&M.

Radio frequency identification (RFID) is an automatic identification technology which identifies physical objects individually according to their unique identifiers (ID) recorded in each RFID tag. Many business processes require the integrity verification of a group of objects in addition to individual object identification. This paper proposes “group coding” of RFID tags with which we can verify the integrity of groups of objects by writing parity check data to the memory of RFID tags. It was revealed by simulations and experiments that we could determine the number of missing RFID tags up to 10 with accuracy over 99% when we write 96 bits of the checksum data to 20 RFID tags. The whole duration of group decoding measured in the experiment was approximately 2 to 3 s. The time to compute group encoding and decoding was in the order of several milliseconds and thus negligible. The RFID inventory accounts for the majority of the duration. Note to Practitioners-Current RFID features fast identification of many physical objects. However, the integrity check of a group of objects is usually done by looking up a packaging list or a shipment list in EDI, which requires a network connection. Our proposed “group coding” of RFID tags can perform the group integrity check without a network connection. In addition, when the integrity of the group is infringed, the group coding can determine the number of RFID tags missing from the group. These features of group coding can reduce the cost of looking up shipment lists and locate missing RFID tags. The accuracy of the determination is controlled by adjusting the size of data written in each RFID tag. Adopters of group coding can select the optimal performance of group coding from the requirements of the accuracy and constraints like memory consumption of RFID tags.

In this paper, we propose a new criterion for the extrinsic information transfer (EXIT) analysis in the spectrum-overlapped resource management (SORM) for a broadband single carrier transmission. In the SORM technique, each user can ideally obtain a maximum channel gain by allowing overlapped allocation, assuming the soft canceller with minimum mean square error (SC/MMSE) turbo equalization for multi-user detection. When the interference is not completely removed by SC/MMSE turbo equalization, frame error rate (FER) remarkably degrades. To solve this problem, we proposed a new criterion which is used for design of error correcting code in order to improve convergence property of SC/MMSE turbo equalization without large redundancy of channel code. In the proposed criterion, we design the decoder so that the decoder's EXIT property is fitted to the upper bound of equalizer's property and the channel code sharply improves mutual information (MI) in the lower amount of input MI. This paper evaluates FER performance with the irregular low-density parity-check (LDPC) codes designed based on this criterion. As a result, this paper shows that the irregular LDPC code designed based on the proposed criterion for the SORM outperforms conventional codes.

This paper proposes an adaptive Overlay Multicast protocol for real-time group communication in a heterogeneous environment. Overlay multicast technology relies on end nodes by delegating the multicast functionality from routers in IP Multicast. Overlay multicast research has two major issues to consider: heterogeneous resource environment and instability of end nodes. In our protocol, data is divided into multiple layers using abstract layered data structure. The number of layers is used for the main metric to construct the multicast tree to satisfy the demand for end nodes resource environment. Furthermore, multi-path layer distribution method for fast recovery from multicast tree partition and congestion avoidance method are proposed to deal with the unstableness at end node.

We propose a new adaptive modulation and coding (AMC) design for wideband orthogonal frequency division multiplex (OFDM), which is called "stable quality - subcarrier-wise AMC" (SQ-SAMC). In SQ-SAMC, a modulation and coding scheme (MCS) with respect to each subcarrier is selected in consideration of the channel variation and the expectation of the carrier-to-noise power ratio (CNR). Our simulation demonstrates that SQ-SAMC firmly maintains the target block error rate (BLER) and achieves a higher throughput than conventional SAMC under a quasi-static condition at a radio frequency of 5 GHz and round trip time of 5 ms. Furthermore, even in typical pedestrian cases, it satisfies the target BLER, which was never possible using conventional SAMC.

This paper proposes a novel technique to enable flow-level multi-path forwarding on IPv6 networks. Generally on such networks, any packet from a node is forwarded toward a destination along the same path, even if some of the packets belong to a different flow with different characteristics. In accordance with packet characteristics and to fulfil demands such as traffic engineering and QoS routing, flow-level multi-path forwarding allows explicit selection of the paths on which to send packets. Multi protocol label switching (MPLS) technology has been used to perform this function so far. However, to apply MPLS on an existing IPv6 network, all non-MPLS-enabled routers in the network must be replaced with MPLS-enabled routers. Therefore, the migration cost is generally expensive. Our previous work has proposed a technique called flow-mapping explicit host routing (FMEHR,), that renders similar results to MPLS using unused address spaces such as IP private addresses. This paper describes the FMEHR concept and its realization on an IPv6 network and discusses its characteristics.

This paper tries to tackle the problem of providing retrofitting network QoS in clustered configurations. For this purpose, we designed a QoS manager which runs on each of the internal cluster nodes and controls network I/O of local interface cooperating with peer managers on other nodes towards a certain QoS policy. First, we show the design of control framework, contending that an end-host manager-based mechanism is a desirable approach, which utilizes an end-host oriented network control primitive, Netnice. Second, for flexibility of configuration, we propose object-oriented modeling of the QoS manager with event-handler based configuration mechanism, and show the design of an object-oriented configuration language that allow simple and flexible definition of QoS policies. Lastly, results from two simple experiments with a Web server cluster are analyzed.

This paper presents several interesting technologies that will support the next-generation of mobile wireless communications. First, a higher data transmission system based on the Personal Handy-Phone System (PHS) is introduced which provides 64 and 128 kb/s data services. Multi-slot channel assignment, which decreases blocking probability, is also presented. New wireless access, called PHS-ODS, is proposed. This can adaptively determine whether a received signal is voice or data, and forward the signal to the user's voice or data terminal as appropriate. A wireless agent that combines the conventional mobile agent with information specific to the mobile terminal environment is discussed. Furthermore, the application of AO/DI (always on dynamic ISDN) to wireless system is discussed; its concept and simulated effective data transmission speed are described.

Label-switching technology enables high performance and flexible layer-3 packet forwarding based on the fixed-length label information that is mapped to the layer-3 packet stream. A label-switching router (LSR) forwards layer-3 packets based on their layer-3 address information or their label information that is mapped to the layer-3 address information. Two label-mapping policies have been proposed. One is traffic driven mapping, where the label is mapped for a layer-3 packet stream of each host-pair according to the actual packet arrival. The other is topology driven mapping, where the label is mapped in advance for a layer-3 packet stream toward the same destination network, regardless of actual packet arrival to the LSR. This paper evaluates the required number of labels under each of these two label-mapping policies using real backbone traffic traces. The evaluation shows that both label-mapping policies require a large number of labels. In order to reduce the required number of labels, we propose a label-mapping policy that is a combination of the two label-mapping policies above. This is traffic-driven label mapping for the packet stream toward the same destination network. The evaluation shows that the proposed label-mapping policy requires only about one-tenth as many labels as the traffic-driven label mapping for the host-pair packet stream and the topology-driven label mapping for the destination-network packet stream.

Character recognition techniques are expected to be used for document input. Their recognition accuracy is however not always high for handwritten characters. Since the confirmation correction input mode, used currently, becomes inefficient when there are many recognition errors, input methods relying solely on this mode are not suitable for document input when recognition accuracy is low. The paper proposes a document input method that selects the optimum input mode based on character recognition accuracy. This method automatically selects the optimum input mode using the relation between recognition accuracy and input efficiency and can increase overall input speed (the number of inputted characters per unit time) for any accuracy. Experimental results using handwritten documents verify that with this method, input speed increases as a whole in comparison with input methods using a single input mode.

This paper describes an image processing expert system for images of footprints used in criminal investigations, and user interface with this system. The purpose of this system is to increase the efficiency of footprint image processing through improved footprint image quality and automatic footprint pattern extraction. In footprint image processing, the most difficult issue is to carry through the complex processing sequence brought by the variety of pickup methods depending on the condition of pickup places, various patterns of footprints, noises and so on. Because this system constructs usable processing sequences for input images automatically by using knowledge of the image processing and has friendly user interface, not only police investigators but general police officers can deal with image processing easily. In the pattern extraction, a practical processing sequence for various footprint images is constructed through the simulation over 37 footprint images, and the usefulness of the expert system is ascertained experimentally.

The feasibility of using isodensity lines for a human face identification system is demonstrated through experi-mental investigation. Instead of using feature points extracted from the faces, as is done in the conventional matchingsystem, the technique presented uses gray level isodensity lines of the faces By comparing the shape of isodensitylines, people can be identified. The identification technique proposed has the following advantages over conventional

Presents a high-speed morpheme-extraction system that extracts morphemes from a phoneme string using the characteristics of a dictionary database. To realize this, a dictionary database access method, a tree-structured index and a parallel index-access technique are introduced. The tree-structured index is divided into an upper part and a lower part, and it is structured to execute parallel accesses. The optimum index structure, which can realize the maximum performance/cost ratio of the morpheme-extraction system, is obtained by evaluating the memory contentions and the amount of memory. This system with its parallelized index is expected to perform morpheme extraction as fast as speech input.>

In an earlier work, we have developed a new principle of optical microscopic tomography, by which an inside optical density distribution of a 3-D biological sample can be visualized without physically slicing. However, since the system is angularly band-limited, the spatial resolution (especially, the longitudinal one) is poor. In this paper, we describe a numerical method to improve the resolution of the reconstructed 3-D image by constraining the reconstructed density to be nonnegative. The method requires much smaller computation complexity than the conventional quadratic programming when the number of variates (pixels or voxels) are large (in the case of 3-D imaging, for example, 100×100×100). Experimental results by the proposed method with real data of a biological sample are shown to demonstrate the effectiveness of this method.