In edge computing, flexibly offloading or handing over computing workloads among devices, edge, and cloud, achieved by live migration, is crucial because of its hierarchical and heterogeneous structure. Implementing the process migration requires the runtime system to capture and restore the state of a running application at any arbitrary time. WebAssembly (Wasm) has attracted attention as a common platform for edge computing since it provides not only architecture neutrality and secure sandboxing as a lightweight VM but also performs at a native-level performance with AOT/JIT code optimization. Unfortunately, the different code optimizations in various Wasm runtimes make it harder to insert instrumentation code into application binary at runtime. We are currently developing a self-hosted Wasm runtime, i.e., a runtime that can be executed on another runtime as a Wasm application instrumentation mechanism while handling the runtime heterogeneity, including AOT/JIT code transformation. One of the major concerns in our proposal is the overhead caused by the intervention of another runtime for instrumentation. This study discusses the feasibility of a self-hosted runtime with instrumentation for obtaining the application's running state by comparing it with existing methods and evaluating it through preliminary experiments.

Web services have seen early adoption and rapid growth with the introduction of various web system frameworks, and not only large companies but also smaller businesses or individuals can provide their own web services offering access to their products, entertainment, and information. Therefore, as the number of Internet users increases, especially with the spread of smartphones, even relatively small web service infrastructure need to have both high access performance and availability, although the cost of additional computational resources and redundant servers may be hard to bear depending on the load. We focus on the fact that the performance characteristics may differ depending on the internal implementation of the operating system (OS), even when the available computing resources are the same. This paper investigates the possibility of developing a system that achieves both high access performance and availability of the web server by dynamically switching the OS on which the web server is running, without requiring additional computing resources or using redundant servers. This paper identifies the differences between Linux and FreeBSD in terms of network processing and describes the mechanism of process migration among heterogeneous OSes to switch the OSes. It then demonstrates the feasibility of our approach with experimental results on the performance characteristics and load tolerance of a web server in operation when the OSes are dynamically switched.

ROS2 (Robot Operating System 2.0) has been being developed from scratch in order to support new applications. One of the most significant change in ROS2 is to follow the DDS standard specification as an interface of the inter-module communication. Currently some of companies and OSS communities provide DDS implementations which have different characteristics such as using the shared memory. The current implementation of ROS2 allows to specify only one DDS implementation to be used in a system through application code or the environment variable at running, nevertheless each communication may have different characteristics and each DDS implementation may be optimized for different communication types. This research proposes a mechanism to allow multiple DDS implementations existing in a system and to dynamically bind one into each communication. The proposed mechanism can estimate communication area, maximum data size, requirement of the QoS control, for each communication channel and then it can select a proper DDS implementation. We clarify that the current available DDS implementations have different characteristics, and then describe implementation of the DDS dynamic binder mechanism.

This paper describes a framework for developing mobile software robots by using the PLANET mobile object system, which is characterized by a language-neutral layered architecture, the native code execution of mobile objects, and asynchronous object passing. We propose an approach to implementing mobile Web search robots that takes full advantage of these characteristics, and we base our discussion of its effectiveness on experiments conducted in the Internet environment. The results show that the PLANET approach to mobile Web search robots significantly reduces the amount of data transferred via the Internet and that it enables the robots to work more efficiently than the robots in the conventional stationary scheme whenever nontrivial amounts of HTML files are processed.