Peer-to-peer networks, such as IPFS, adopt the distributed hash table (DHT) to find contents efficiently. IPFS uses Kademlia DHT as a routing scheme to effciently lookup any content with CID (content ID). However, due to the completely matching nature of DHT, IPFS does not have any scheme to lookup content with one or more attributes and ranges. Thus, it cannot be applied to a situation where several contents can be retrieved in sensed data such as an IoT network. In this paper, we propose a multi-attribute and range query scheme for Kademlia DHT in IPFS. In our proposal, several responsible nodes are used for maintaining a specifci attribute prefix and having CIDs for mapped contents. As a result, once a query arrives at a responsible node, any contents with mapped attributes are retrieved.

In order to simplify deployment and management of IoT services, Network Function Virtualization (NFV) and Service Function Chaining (SFC) are promising solutions, and much researchers have conducted these topics. To enhance the reliability of former research efforts, in this paper, we propose an orchestration framework for IoT-centric SFC by using Docker and Kubernetes. The framework enables an automatic IoT service deployment by satisfying service requirements and computing and network resource constraints. In such deployment, we apply a Virtual Network Function (VNF)/Service Function (SF) placement problem to achieve efficient utilization of the resources. We set an objective function as minimizing both numbers of SF instances and communications and build a mathematical model based on Integer Linear Programming (ILP). To validate it, we implement a model for the framework and evaluate the performances by carrying out a numerical evaluation and a real experiment. From the evaluation results, we confirm that the proposed approach can reduce the number of SF placements and the number of communications among SF instances.

Distributed Hash Table (DHT) has been widely applied to peer-to-peer (P2P) applications for efficient content lookup mechanisms. IPFS, one of the distributed systems for sharing files, websites, and data on a worldwide scale, adopts Kademlia as one of the DHTs, that is included in libp2p on the network layer of IFPS. Though DHT-based content lookup can scale in the number of peers, how to control lookup performance, e.g., lookup latency and lookup hop count, is one of the issues for a very large-scale network. Thus, it is necessary to guarantee both the lookup latency and the hop count even if the network scale becomes larger. In this paper, we propose a Kademlia alternative, called KadRTT, that reduces both the lookup latency and hop count. KadRTT has two functionalities, i.e., (i) RTT-based lookup target selection not to increase the maximum hop count, and (ii) uniform ID arrangement for each k-bucket to shorten the initial ID distance from content ID. Experimental results by the simulation show that KadRTT outperforms other Kademlia-based DHTs in terms of lookup latency and hop count.

Virtualized service and network functions are deployed on virtual machines (VMs) to realize essential processing to realize service function chaining (SFC). Issues on SFC is SF allocation to a VM and to minimize the response time and number of function instances. In this paper, we propose an SF clustering-based scheduling algorithm, called "SF-clustering for utilizing virtual CPUs" (SFCUV), to solve the SF allocation and SF selection problems simultaneously. Experimental results show that SF-CUV can utilize vCPUs to minimize the response time.

Parallelization paradigms for effective execution in a Directed Acyclic Graph (DAG) application have been widely studied in the area of task scheduling. Schedule length can be varied depending on task assignment policies, scheduling policies, and heterogeneity in terms of each processor and each communication bandwidth in a heterogeneous system. One disadvantage of existing task scheduling algorithms is that the schedule length cannot be reduced for a data intensive application. In this paper, we propose a clustering-based task scheduling algorithm called Clustering for Minimizing the Worst Schedule Length (CMWSL) to minimize the schedule length in a large number of heterogeneous processors. First, the proposed method derives the lower bound of the total execution time for each processor by taking both the system and application characteristics into account. As a result, the number of processors used for actual execution is regulated to minimize the Worst Schedule Length (WSL). Then, the actual task assignment and task clustering are performed to minimize the schedule length until the total execution time in a task cluster exceeds the lower bound. Experimental results indicate that CMWSL outperforms both existing list-based and clustering-based task scheduling algorithms in terms of the schedule length and efficiency, especially in data-intensive applications.

Data transfer of large files over the Internet is often performed using Peer-to-Peer (P2P) technology. BitTorrent is the most popular P2P content distribution application. In general, BitTorrent users have much higher download bandwidth than upload bandwidth. It leads to bottleneck problem under the lack of the upload bandwidth, and it drastically degrades the performance of the overall system. In this paper, we propose a method to utilize idle upload bandwidth of helper in order to improve the file sharing efficiency on the BitTorrent. We also evaluate the efficiency of the proposed method by using simulation.

This paper presents the symbol presentation method for Universal Design (UD). Current symbol presentations for UD focus on how to design a simple and perceptible symbol for as many users as possible. As a result, the same symbol is presented to every user and therefore some users with specific attributes (e.g., color-blindness, cultural or physical conditions) can not perceive the symbol appropriately. Thus, we propose the user-adaptive symbol presentation in which optimal components (color, shape and background) for a symbol is automatically selected using Analytic Hierarchy Process (AHP). We also present how compatibility among those components should be taken into account in order to be intuitively perceivable as a whole pictogram. The experimental comparisons show that our proposed user-adaptive symbol presentation has considerable improved satisfaction related to visual effects and distinction of color/shape than the conventional approach.

This paper presents the interactive web interface for inquiring about the long-term care insurance system in Japan. In Japan, health care services provided by the long-term care insurance system takes costs depending on the health care level. Although the system has been revised several times, such revision made the system more complex, so that a web-based system by which every people can accurately and easily ask about the long-term care insurance system is needed. Thus, the proposed interface in this paper has two points to achieve the requirement. First point is to show only basic information related to selected options on the web page. The second point is that dependencies (parent-child) among each category for inquiring should be presented on the web page to make the user understand each ranges of the category meaning. The experimental evaluation shows that our proposed presentation method using the web interface has advantage on perception among categories, human error, and user-friendliness.

Grid computing has been widely spread in pragmatic areas and scientific research areas in order to achieve more powerful computation than ordinary computation by single computer. Globus Toolkit4 (GT4), which has been the de facto standard middleware in Grid, gives to us many chances of submitting jobs, especially using WSRF technologies. However, in case of cluster type grid using GT4, rules for job execution depend on a local scheduler (LS) which interacts with WS-GRAM in GT4, so that clients can not reflect their own rules to behaviors in each worker node. In this paper, we formulate those potential problems and solutions based on our proposed architecture in, whose main feature is to monitor resource property (RP) in WS-GRAM and notify its status to worker nodes. Then we describe how to implement a mechanism for monitoring RP in WS-GRAM to achieve the transparent delivery of client's rules to worker nodes. Our experimental results show that our proposed architecture can be incorporated in WS-GRAM without difficulty.

In recent years, Web service technologies are becoming more and more important communication scheme for grid environment. WSRF-based resource management components, such as WS-GRAM in GT4, lay emphasis on how to make existing procedures such as local scheduler be invoked via HTTP, so that they inevitably have two problems described below. (1) If assumed environment is cluster type grid, each worker node does not have access scheme to any information included in resource property of master node. (2) As a result, the contents of information sent to clients is forced by the local scheduler and therefore clients can not control job status in accordance with their own policy. If those two problems are resolved, any client's own resource management policy can be reflected on worker nodes. In this paper, we propose a method for resolving those problems in order to realize the interactive communication between clients and worker nodes for WSRF-based cluster grid.