Shusuke Okamoto

Design of a superscalar processor based on queue machine computation model

The queue machine computation model is an evaluation scheme for expression trees, in which the input operands of operations are taken from head of a queue, and its result is put onto tail of the same queue. A series of operations for this model are generated by traversing the expression tree(s) from its leaf nodes in reverse of the breadth-first ordering. Since nodes with the same level in an expression tree can be processed concurrently, the generated operations can also be processed in parallel without reordering. In this paper, we describe a design of superscalar processor using this computation model.

Easy creation of network-based interactive animations using Islay

This paper describes an implementation of our tool for authoring network-based interactive animations. The tool is named Islay. The interactive animation addressed in this paper is one of computer animations whose scenario is varied according to key and mouse inputs by viewers. An animation made by the tool is constructed as a collection of characters. The behavior of a character is defined by a state-transition diagram. The GUI editor makes it possible to create a simple animation by mouse manipulation within half a minute, if the prepared pictures are used. The animation interpreter in the tool serves multi viewers who operate each network-connected computer. The core routine of the interpreter runs on each viewers computer in this case. The communication between the computers is implemented using our software DSM (distributed shared memory) library. This paper shows the implementation details of the interpreter, as well as the brief overview of the rest of the tool.

A moving home-based software DSM system

This paper describes a moving home method for home-based software distributed shared memory systems. In our system, a home node users records for access to the shared page to determine the moving its role of home. Each time a home node receives a service request for the shared page from a non-home node, it records the node ID and the type of access. If the number of the access records exceeds the threshold of request counts, the home node decides whether the non-home node, which sends the request, is suitable for a new home node of the page. To evaluate our moving method, we have implemented a prototype of DSM system from scratch. The result of our performance evaluation using SPLASH2 benchmark programs shows that our method improved the performance of the system over the fixed home node methods.

A Network Game Based on Fair Random Numbers

A compromising technique is proposed for deterring clients from cheating by robot players in skill-based real-time network games. This technique is to inject a fair random noise into the manual input for a real-time game modeled as a chaotic dynamical system. The fair random noise is determined by means of the bit commitment protocol so that neither host nor client can control the noise in their favor. A scenario possibly plotted by a robot player for its victory may be spoiled by slight noise injection because of the sensitivity of chaotic systems to the input. The noise injection brings a luck-based factor into a skill-based game. In this sense, the technique proposed in this paper is not a solution but a compromise for the inherent problem of robot players with the skill-based network games. An example implementation of pinball is presented.

IslayTouch: an educational visual programming environment for tablet devices

Educational programming languages are programming languages that have been designed for users without programming experience, with the purpose of teaching them the skill of logical thinking or as an introduction to regular programming languages. Although these languages are relatively easier for beginners, difficult concepts of regular programming languages are still being introduced into some of them. As a new approach to this problem, an educational visual programming environment called Islay has been developed, in which the concept of state-transition diagram is used to compose a program. As a result, Islay becomes even easier for beginners than some other educational programming languages. In this research, a new version of Islay is developed as an Android application, with more features being added and a new user interface that is suitable for tablet devices.

Instruction set architecture to control instruction fetch on pipelined processors

Instruction fetching is usually the default action related to the program counter, and it is affected by the execution of a branch instruction. However, the processor does not know about the timing of a branch until it fetches a branch instruction, and it must start processing the branch just after fetching a branch instruction. Hence this situation causes control hazards. To solve this problem, the authors are engaged in studies on the control of instruction fetching and have developed a new mechanism as the first solution. In this mechanism, instructions to control instruction fetching are inserted into programs. The processor can identify these without decoding, and it processes in parallel with the other instructions. The paper describes the instruction set architecture of this mechanism, and describes its performance evaluation using a software simulator.

A C++ Header Library for Web Applications

This paper describes a C++ library to build web applications. The idea is borrowed from Node.js and Express.js which are a rapid web development framework for JavaScript. Our library consists of a few header files so that it can be available by including them into a source code. The API uses some C++14 features, especially auto type, and the program which uses this library becomes concise and clear. In this paper, the design policy, several sample programs and its implementation are presented.

Access control for a confirming attendance system

In a university, information about pertaining to an individuals presence in a room is vital. For instance, when a student calls on a teacher, the teacher might not be in his/her office. In this paper, we propose a system for confirming attendance at work through a web application. This system provides information regarding whether a teacher is in his/her office or not. Further, this system also provides information about the schedule of classes, meetings, and official trips. In addition, the proposed system limits the public access of this information because this information is a personal information. On the other hand, the proposed system provides additional information according to the relationship between the users on a social networking service, because the teachers family and friends also might want to see the schedule. Therefore, we need a method to confirm the teachers relationship with these users who access the information.

Interactive Animation Authoring Platform Based on State-Transition Diagrams that Runs on Android Devices

An interactive animation is a presentation of moving pictures that behave dynamically according to the input from users. It can be composed of animation characters modeled as finite-state machines. Based on the fact that the behavior of a finite-state machine can be defined by a state-transition diagram, an interactive animation authoring tool called Islay has been developed. Islay allows users to create interactive animation simply by drawing state-transition diagrams on a GUI-based editor. Up to now Islay mainly runs on the PCs. But we cannot use it on the portable devices that have become popular recently. In this research, a new version of Islay that runs on Android devices is developed with its user interface adapted to the touch screen interface.

A Graphical Front-End Interface for React.js

We present a graphical front-end interface for creating dynamical web pages by means of React.js. Its user does not have to write JavaScript codes for specifying the dynamical behavior of the web components but has only to draw state-transition diagrams graphically on the developed graphical editor. Using the graphical editor, the user composes a state transition diagram that specifies the dynamical behavior of each web component in terms of circles representing the states of the component and arrows representing the conditioned transitions among the states. Then the developed translator converts the state transition diagrams into web components of React.js in JavaScript that compose the target web page. This system of the graphical editor and the translator enables general users without knowledge and experiences in programming to create dynamical web pages. Wanna-be programmers may start learning JavaScript and React.js by comparing their diagrams and the translated JavaScript codes.